Some of these boats are abandoned, some have people living on them.... They are usually both an eyesore and are equally capable of creating an environmental mess.
How do you determine if a vessel is abandoned? I haven't been aboard the Folly
since last August and probably wont get back to her until late this summer as I'm working out of province. I do have someone checking on her every once and a while and after all the big blows, but it would be very easy for someone to label her abandoned, as I'm not there every weekend checking on her as some of those with boats moored near me are. And she's not the prettiest boat in the bay... yet(yes I know she's a CAL 25 but a guy can dream can't he?).
You may look at her and see eyesore, but I look at her and see adventure.
It all depends on the eye of the beholder. My friends and I have great fun exploring the M.V. Dominion in Cowichan Bay at night, when she goes it will be a sad day, in my book at least.
As for the potential for an environmental mess, how many coastal municipalities dump their sewage in the ocean? If all these eyesores were to sink en-mass I think the damage would be far less.