The store says "Your bike would require drilling through the crown of the front fork in order to mount the brake caliper. This procedure would compromise the structural integrity of the fork, and isn't recommended."
Considering I think having only a coaster brake is maybe 7/10 safe, and my lack of muscle memory/confidence with it reduces to probably 4/10... how unsafe will that compromised fork structural integrity be? i.e. would I be better or worse off?
This is a 'ride to the shops' bike riden very sedately and doesn't get banged about in storage.