I have attended a fair number of live, in person auctions that were not associated with trains or collecting. Sometimes shill bidding happens.
I don't know for certain whether I've ever had to pay a higher price for something due to shill bidding. I assume that I have. I don't loose sleep , or even think about such matters. Since I never bid more than I am willing to pay, I am always happy in the end.
With EBay's bidding model, where you only pay the increment over the next highest bid, I've gotten a fair number of items well below my ceiling.