Using phone as a key. Not a good idea.

[slipnslider]

Or thumbprint technology, like our tablets and phones.

That'd be fun in a rainstorm. Howbout a fob? Sometimes the answer is LESS tech, not MORE.

 

[CWFLY]

Yeah, good point.
I had to replace a FOB once, and it cost me well over $300. So every time I hear the word I cringe. Optional FOB... I don't see why not.