I have a 4 mile commute one way to school everyday and on Wednesdays it is a 10 mile one way commute. I bike on bike trails and often times there are road bikers, or groups of road bikers, that ride on this trail. I was wondering what is the etiquette of drafting these groups to help ease my commute.
I dont wear the bike shorts or jersey when commuting, and usually just jeans and some t shirt and I also have a backpack on, so I definitely do not look in place with them. Do road bikers mind you drafting them for a few miles?
I try to not make it a race but some of them speed up when I start following them. I have had people draft me and it does bring out my competitive streak so I understand that. But when I'm following someone, I am doing it purely to save my energy.

Sometimes when I'm really lazy and I really dont feel like biking, I'll cruise along the bike trail at 13mph, and wait until a group of bikers pass at 20mph and right away start following them all the way home. To me this is much more interesting than fighting a headwind all the way home by oneself.

What do you guys think?