I've been using the last year thickslicks to driver mainly inside my city and I usually tried to don't go through anything else but asphalt to prevent punctures.
I've been wondering if going through a rocky path (or something similar with lot of little rocks) with thickslicks (700x28) and pressure around 100psi is more likely to get a puncture than the traditional wider and with tread tires that most MTB bikes have.
Example with no tread:
And with: