Stickies wouldn't do the job.
I think the best way would be to sent and auto-generated PM to all new users like:
"Welcome to the community!
Before posting, read this carefully:
1-Guns cannot be ordered from outside Canada, they'll get seized
2-Do a search before posting
3-use correct grammar
4-the list goes on and on.
Well, the list shouldn't be too long, it would discourage most of them.