When you work with a US client, the client will ask you to file a W8 form and once you put their UAE, this means the US client should withhold 30% of the payment amount to you, that's the US client's obligation.If you don't have any US presence and work is performed outside the US I don't it's the case.
of course, there is a case when the client doesn't hold it and it could be a case for them to pay 30% on top of your contract.
in general, if they have good accounting, they will withhold for sure.
I'm talking about B2B contracts.
if you sell products it's a different story but if you provide self-service, I can't see any other options.