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.
this is a pretty common mistake which even veteran gamblers still suffer. we all know that carelessness isn't the main reason why people sometimes overlook about this rules and regulations, sometimes being excited to try something new out of pressure from other people can also overlook this rules, and much more common reason is due to laziness. also there's this rules that are not specially highlighted in order to confuse bettors, which are commonly seen on shady gambling sites or newly created ones without future plans and just existed solely to rob money for those who wanted entertainment. this is usually what happened in my country, there have been many issues like losing their money inside their e-wallets (our locally provided e-wallet) after linking their accounts to new gambling site. due to so many influences like social media influencers promoting, people claiming they won a lot and actually claimed their prizes and the fact that you can gamble with only small amount is the trigger why most of my fellow acquiantances ignore their security in exchange of money. to be honest it is sad and at the same time it's destroying the image of gambling which can lead to the future banning of all online casinos in our country, but most of the fault is on their users for not securing themselves.