If Parbond is illegal, better lock me up! I have recently bought, at our local RV dealer, enough to stick Ted Kennedy to George Bush. I purchased and have used; silver, clear and grey. Can't beat the stuff! The squirrels, mice, birds, ants and spiders are as plentiful as ever, but the leaks stopped!
Crack is illegal, but if you wanted some you could probably find it. Illegal or not, if I wanted some Parbond, I would find it and use it.
Luck to you!