Haha, I would either let them rot or crucify them. They should have every right to say how they feel, but no right prevent other people from getting married. They'll probably just get arrested and processed like normal people. Because to chain would require vandalism (puting spikes in the wall), or wrapping a chain around the building, and neither of those are acceptable forms of protest. It also breaks some other regulations and they'll get slapped with those. Good luck with that one...
PS: Don't be ignorant and intolerant by doing this or premoting this.
I'm not from Canada so I'm just speaking my mind... but I don't think it's illegal to quote bible verses as long as it isn't in an intolarant manner. For example: if some guy on TV or the radio was going off on how all homosexuals are going to hell and how their so "ignorant" and such... I think this is the kind of thing the law is probably supposed to protect. Honestly, in a case like that, I would support the law 100%. Some Christians are so mean and intolorant to homosexuals and I don't think it's cool at all... Jesus would be tolorant and willing to help them and be their friend. He wouldn't tell them to go to hell.
By the way... I don't exactly think that crucifying Christians is that tolerant compared to a nonviolent protest. Yes, in a situation like that there would probably be vandalism charges but they aren't killing or hurting anyone.