Homeless in Vancouver: A sign of particularly brazen thieves?

As I locked up my bike yesterday morning to the bike racks outside an office building on the western edge of East Vancouver, I noticed a sign taped to the inside of a window beside the racks:

“Do not park your bike here unless you have an all metal “U-lock”. Otherwise it will not be here after work!!”

I’ve never figured out if more exclamation marks increase the importance of a statement additionally or exponentially and I’m not even aware there are other U-locks besides the all-metal kind.

Also I’m not sure who put up the sign.

Probably it was the building management giving us fair warning about the activity of bike thieves, but couldn’t it have been the thieves themselves—giving us a sporting chance?