I own a number of VRBO rentals (and have rented as occupant a number of units also) and have the following thoughts:
1. If you were going to have additional guests enter the rental that should have been disclosed to the owner. Frankly, it happens all of the time and as long as the additional guests are not sleeping over I am usually fine with it. Often pricing is based on the number of guests and allowing additional people to use the unit but not sleepover is a gray area. What if you invited 6 additional people over? It is hard to draw the line. Nevertheless, I believe you should have informed the owner.
I agreed with his quote.
I have airbnb place, but this case owner maybe hired a company to watch for the reservation. So from the company's safe side not to be grouch by owner, it would have been more strict in this case.
So as a host, biggest concerns are what kind ppl come and they would maintain the property well. I also have no anyone without pre-approval comment on my house rule. Because without it, ppl would think like you. They can utilize my property to store luggage or use bathroom or shower etc. Or dont need to find a place to chill out. etc. This misunderstanding happen all the time if there is no rules. some of my guests visited their friends and bring them over here as non overnight. Then, I would alarm those ppl to monitoring closely not following rules.
If you did asked about extra guests even of a short period time, it would have been better. at least you were fine until this violation.
But from my perspective, blocking camera is big red card. I think thats why you were kicked out. you brought guests without telling and blocked camera. Host's concern and anxiety will go up. They know they followed where they can install the camera not to show privacy. so from their viewpoint, no problem.
Also, due to your violation, it is cancelled, i am not sure they charged the whole period time or not. But they are losing money due to your fault. They would try to collect money as much as possible.
This forum ppl, well education and wealthy, but out there, there are so much bad ppl. I had a guest booked to do drugs with non registered guests over.
It is hard to present what kind person we are. But from my experience, who follow rules are very considerate stay in the property.