Since you are exporting the finished goods, yes, you would not charge PST. But if your customer is importing the goods into Ontario and not paying sales tax (self-declared, on all imported goods) they could be subject to prosecution and penalties, putting them out of business.Thanks for the link but we knew all that. And yes, the point about materials being used in the construction of the exhibit is RST exempt and we had the certificate for just that purpose.
One of the trick aspects of this is: construction and delivery of an exhibit, to a customer based in Ontario, but they take first delivery of it in the US. LOL. We did that many times and never really did figure it out.
And that sort of illegal tax evasion (in the scenario outlined) costs all taxpayers.