Please name a successful startup that began its earliest stages in an office. Google, Excite, Yahoo, Dell, Msft, Apple? They all started in dorms/garages/apartments.

Not saying its not possible or some dont prefer it, but the majority of successful ones do not. That is just historical fact.

But its a moot point as it sounds like (according to rms) the group office space is indeed optional with Techstars..