The VAST majority of people who posted that they don't tip are regional pilots. I'm sure they are those that do and that there are mainline pilots who don't. Ask the next van driver at a hotel that both regional and mainline use who generally tips the best.
I think most regional pilots tip. The real problem lies with regional management's low cost hotel process. They cut deals that allow the hotels to schedule multiple pick ups and no assurance that their crews are given prompt service is required. I have been told by managers that our crews are not given any rides to food establishments etc, because our managment pressed for a cheaper hotel deal. Same thing about free breakfasts, etc. I was loudly informed that I was not welcome at a breakfast buffet that had been free a week earlier because our management gave it up for a one dollar reduction in the rack rate. It cost me 9 bucks including the TIP...... Pilots like to bash each other..... try saving it for the true scumbags at corporate....