You lose power, the service has already been rendered but you've not been paid yet. You can't negotiate for payment by threatening to withhold service. Same th

You lose power, the service has already been rendered but you've not been paid yet. You can't negotiate for payment by threatening to withhold service. Same thing happens to freelance developers and why some add kill switches[1]. You deliver, the client then says "It's not quite what I asked for, I'll give you Nothing/10%/50%/80% of what we agreed". Obviously it's worse for call girls as they can't take you to court in most countries, hence why they always ask for money up front. Their post-service negotiating position is extremely weak. So no money up front, no service. [1] I personally think that as long as you make it clear to the client + part of the contract that they only have a temporary licence key until full-payment, kill switches are fine. Adding it on the sly is not.