Say for example - I'm a regular customer at a restaurant but on this particular occasion I've phoned first to order takeaway. So on the way home from work I drop in at the restaurant to pick up the pre-ordered takeaway.
While I'm hanging about waiting for the food to be brought out from the kitchen, a rude, pushy waiter starts hassling me to sit down and eat in. I explain that I've already pre-ordered takeaway. He then hassles me for tips, claiming credit for non-existent service.
Would you give him the tip?
I daresay most, if not all of you would not, based on the fact that you weren't eating in, he had done nothing to "serve you" as a waiter, and therefore he did not earn his tips. Notwithstanding the fact that he was arrogant and rude to you on top of it all.
Relating this scenario to the first poster's circumstances above, the logical reasoning for earning the 'tip' or the 'commission' remains the same.
The only difference is, in my scenario, the waiter is ripping off you the customer. Whereas the GC salesperson above is ripping off his employer and going against the tenets of customer service by placing GC customers under duress and intimidation and being rude while they're at it.
That's like declaring open season on any potential customer that walks through the doors at GC. Genuine customer services goes out the window.