I draft quite a bit. Only on the road, and only people who look like they’re proper roadies and have overtaken me. I get drafted quite often too. I’d usually say something if I have the breath though, and assuming I’m not behind some ridiculously fast club type, I’d always take turns on the front. I wouldn’t draft as close as I would someone I know though. I figure if I overtake someone and they manage to hang onto my wheel, then fair enough, it’s not like it does me any harm.
It is really nice when you’re at the end of a hard week and some proper fast roadie gives you a tow for a few miles.
On the other hand, most of my riding is in the country on A roads – I have points on my rides where the next set of traffic lights / major junction is five or six miles away, which means you aren’t going to have to brake for a whole long time. I think it is maybe different in cities, because you have to stop and start a lot more. I used to find red light jumping idiots were a problem in cities, because if you had one of them behind you and you slowed down for the lights, they’d often be assuming you’d keep going, and have to skid to a halt behind you.