If I decide to buy an aftermarket spoiler I will definitely have my VW dealer install it. I spoke with a VW Canada rep on the phone this morning, and of course he told me they would not approve the installation of an after market part. I don't think it would be a problem, but like you said, as long as they install it, its a non issue.
Cheers!
P.S. sunny and 29-30 degree sunny weekend here. First really hot weather for top down cruisin'

I found a post on the vwvortex site about an Alberta get together, so a few of us will be getting together on Sunday for an EDA!!