I originally titled this question as "I'm looking for a convenient absolutely fail-safe automatic lock that works all the time". But, judging by some rather cold responses, that title seems to be quite an oxymoron for city dwellers.
Please don't get hung up on the way the question is worded, but rather focus on the problem and on finding solutions. Please use some imagination. Try to think of alternatives that will help to solve the problem.
Two bicycles have now been stolen from me within the last year. Both were mountain bikes. The second was full suspension. I am interested in getting into touring as well. So I'm thinking of 27-speed for my next bike. I also like the full-suspension mountain-bike idea. But before I get another bike I would like to be absolutely sure it cannot be stolen. Of course, that does not mean I will be entirely and certainly successful in meeting that objective. But I live in a small town and am also interested in rural, remote, solitary touring in rural areas distant from metropolitan areas. So professional bike thievery is not a major problem here. There simply are not enough bikes around to make professional bike thievery worthwhile. The problem is more about opportunistic crime and the difficulty of always remembering to lock my bike. It would be ideal if a bike could lock securely and automatically when it is dismounted. Simple motions to lock bike may be easier to remember and undertake rather than always trying to go through a bothersome rigmarole to lock a bike. In this regard, I saw a question dealing with having to lock a bike many times a day and the need to make locking a simpler operation. That question seems to partly address the problem(s) I have in mind. All kinds of compromising situations can arise unexpectedly when bike riding, and it can be easy to forget to lock a bike under such circumstances. So techniques are needed to easily avoid leaving a bike unlocked when such compromising situations arise.
I would like a very convenient, fail-safe lock that does not depend on my remembering to lock the bike every time I dismount. If you think such things don't exist or can't be designed or developed, please try to think of "best-practices" alternatives and techniques that might be useful.
I am thinking that the ideal lock would lock up the bike automatically when the bike is dismounted and could be unlocked only by key or combination or by my presence within five feet, say by a radio chip (perhaps a small RFID chip or other credit-card-like passive responder) carried by me, say worn on my belt.
And of course, the lock needs to be "fail-safe" under all conditions. So it should not lock up when someone is riding it. And since the radio operation would likely depend on batteries, the lock also needs to be unlockable by key or combination when the bike is about to be mounted so that I am not left stranded if the batteries fail. It would also help if the radio operation is very low power so that batteries would last and so that the radio operation would be extremely dependable.
Does anyone know of any such lock or an engineer/manufacturer who would be interested or willing to design, build, and market such a lock at a reasonable price? Are there any such people who use this bike stack exchange? If so, could could you please provide an answer? While a specific lock on the market may perhaps be especially useful, this is really a generic question that includes alternative and potential designs and techniques for solving the problem. Try to think creatively about alternative ways that this problem might be solved.
ADDED COMMENTS Thurs, Mar 26, 2015, 5:23 am PST:
It is clear now that most answerers are thinking in terms of big-city professional bike thievery. But that is not the problem I am faced with. I live in a small desert town, Joshua Tree, CA, although the area has growing signs of ugly, big-city life and all the problems that come with that. I have lived extensively in several different, crowded, congested metropolitan areas myself, and I know from personal experience the kinds of problems that can arise in such an environment. And I sympathize with the "hard-hearted" problems that such a life often engenders. But that is not the problem here. There simply are not enough bikes around here to make professional bike thievery worthwhile. So I think the nature of the problem for big cities is very skewed when that scenario is applied to a small-town area. That does not mean that professional bike thievery won't or does not happen here. I think the problem here is more of a random, opportunistic nature. But the general picture seems to be very different here than in big cities. I am still looking for some creative, imaginative engineering perspective in the answers. I gather that most answerers are not professional engineers familiar with the challenge of creative, imaginative, scientific design and development processes. But I appreciate all efforts to help with this problem.
I realize that, for very many big-city people, professional bike thievery is a very old, thoroughly worn-out problem that does not inspire imaginative, new thinking. It's like "ya, ya, it all started with the Garden of Eden. So what else is new?"
This is my first post on this stack exchange (or any stack exchange for that matter), and I now see that clicking on the "security" tag provides lots of alternative answers, which may be helpful. I do see there that there are some creative engineering designs and some imaginative engineering behind those designs. So that provides some hope.
I might add that, besides relevance for local, small-town life and travel largely for errands and for enjoyable, healthy exercise, I am also interested in solving this (potential) problem for long-distance bike touring which is largely remote and rural in character, that is, remote from metropolitan areas, although I might find some occasional need to visit metropolitan areas; so I definitely do need to be aware of professional bike thievery hazards if and when I do visit metropolitan areas.
I definitely think there needs to be a "rural" tag available for use here.