I think I read somewhere that you can void a new car warranty by boosting someone. I know that the local cab companies won't do it anymore. I once loaned my Passat to a friend who in turn boosted a BMW 325, unfortunatly they got it wrong, killed his dash instuments and my Battery.

As I side note, I see you are from Canada, have you seen the new booster cables from Canadian Tire, they are idiot proof, you cannot hook them up wrong, they have no colour codes, but some of gizmo in the middle that sorts out the current.