Re. wiring two payphone lines together: uh, NO. From a practical standpoint, it will probably drop trouble cards at the CO. From a legal standpoint, it's theft of service, and especially with red boxes etc.; again, a dumb place to make your stand in court.

Well, the suggestion wasn't meant to be taken all too seriously; note the smiley face. :) (Altho I wouldn't be too surprised if someone has actually tried it - you never know...)