simple to handle. for a game or two everytime a character says a vague question like I want to pick the lock look at them and say. "Roll if you are picking the lock" then there is no vagueness. If they continue to argue remind them of how you worded your statement and tell them they can accept it or leave. don't let your players roll back actions because they don't like the consequences. If you aren't firm that kind of player will push everytime. Just don't let them.I’ve been at this almost 40 years and it comes up constantly. Typically when bad things happen to PCs. “I want to pick the lock” very quickly morphs into “I never said I actually pick the lock” once the referee assumes intentions equal actions and applies any consequences to the character based on the assumed action. Some players like to play word games as a shield against bad stuff happening to their PC. So either the player explicitly declares an action or their character doesn’t perform any actions. Having a clear idea of what they intended is really helpful to make sure everyone’s on the same page.