"Let's say I observe an large, (100k+ a year) ebayer who isn't charging GST and PST, even though its obvious he must. "
I am one of those sellers with a business well exceeding $100,000 a year (on and off eBay) and do not charge consumption taxes to my Canadian customers.
"I'm guessing he doesn't report his income either. "
That is insulting! What basis could you possibly have to make such statement?
Many tax registered sellers, on eBay and in the "real" world, sell on a tax included basis or chose to absorb consumption taxes for a group of customers to generate more sales, goodwill and remain competitive with non-registered sellers.
By the way, I was recently audited for two fiscal years, both income tax and GST/HST and the auditor found my books in order. My re-assessment was $0.00.
🙂
"There is no way this is a sensible business practice for him. The margins do not greatly exceed sales taxes."
????
If your margins are less than the taxes, you should look for another business. With sales to Canadians less than 10% of my overall sales, the cost of absorbing taxes is a minuscule percentage of my overall gross margins. That's the way I do business to remain competitive. If you check my feedback rating and DSRs, obviously my customer like it.
It is important for sellers to be honest with their customers. If one is registered to collect taxes (GST/HST and/or PST), the listings should clearly say so.