Most is laziness for sure, thinking that they are already good in understanding the rules but still getting scam or being stuck because of huge wagering requirements as they did not read everything under the terms and agreement, I agree that even experienced gamblers can still suffer from same mistake and will also undergo with working along the site support team.
If you are lucky, you'll be able to solve it, but if not, you will accept the fact that it was in the rules that you needed to follow.
Actually it's not a matter of being lazy to read the rules or requirements that exist in the casino, but gamblers sometimes just memorize the rules from other casinos and think all the rules are the same even though every casino has different requirements and rules.
On other issues, sometimes gamblers are too careless in a hurry to immediately place bets and forget not to read the terms and conditions.