You would have thought so, wouldn't you! However I swear I have seen one chap walk past about 4 bins still cradling a bag full of them-hopefully he was being eco-friendly and taking them off for recycling.
It seems almost entirely unlikely. Saving 'em up in their hundreds to weigh 'em in for beer money?
The main point I was making was that they are being disparaging to someone whilst plainly displaying how they have just spent an afternoon drinking on their own by a fairly deserted reservoir-an eminently more exciting and rewarding experience than birdwatching, of course! .