You mean, is it allowed? Sure. 😉 Gets you into the workshops too, some of which are pretty good. Better plan on spending a few days though, because you'll want at least one full day on the floor.
I always stay at the Holiday Inn Civic Center at 9th and Market. It's a pretty good (10-15 minute) hike down Market or Mission to the Moscone, but unless it's raining, I enjoy the walk. Not the greatest neighborhood either (right next to the XXX district), but the price is right (about $80 last year online) and it's a good hotel with very close access to BART & MUNI and all the buses and trollies running up and down Market Street.
So now my secret is out...