Here's the kicker...your responsibility to accept the trip is NOT ABSOLUTE. Let's say your wife works. If I had 2 RES days at the end of the month, and then I was off for a REG line the following month, and my wife happened to be working on the first day of that month, I would tell the scheduler that I couldn't accept the trip because I didn't have child care coverage. That would be perfectly acceptable, and they would have to find a replacement. There are other acceptable reasons, but you better have your game face on when you pull the trigger, because it may get a CPR (Chief Pilot Report) placed on your line, but you're perfectly within your rights of the PWA to refuse the trip IF YOU HAVE a valid reason. You DO NOT have to work on your days off, but YOU BETTER have a valid reason if you make that call.