Originally Posted by Cycle Pilot

You can actually turn down a trip if it's less than 12 hours and you have submitted a YS. If you have submitted a YS and they assign a trip more than 12 hours out, you have to take the trip.

Section 23 T.

6. A reserve pilot who is proffered/awarded a yellow slip for a rotation with a report that is:
a. 12 hours or less from first attempted contact may decline such award (this is a proffer).
b. more than 12 hours from first attempted contact is obligated to fly the rotation (this is not a proffer).

I use the YS because I can't sit long call from home so I want to fly instead of sitting around the crashpad. Once I arrive in base, I pop the YS in. If they're really short, I'll forgo the YS and put in a GS instead.