It's pretty common indeed but you need to keep doing your part in terms of reading the terms and condition to make sure you'll be able to maximize the uses of the gambling site you pick to play your game, with proper understanding of the requirements you will not be surprise if something is needed to implement since you do your part reading and understanding what is being said.
Accepting the requirements means that you are willing to follow whatever the house is implementing, for you to be able to transfer your money or for you to manage to take advantages of any offers that the house is offering.
Do you know that some persons does not to be an instruction of a particular gambling platform before they participate to that have already cause people things that they don't know or lead them into problems so it is good from my understanding to at least studied a particular platform that you want to partner with very well before you make your bet so that you will not have any difficulties during the withdrawal