Suppose an NPC securely ties up a PC. That's within the scope of a DEX ability check according to PHB, or INT if following the XGE optional rule. The PC determines they want to wriggle free of those bonds. Their decision-making authority hasn't been impacted by being tied up. What is impacted is the outcome, how their character turns out to be able to act in actuality. According to PHB wriggling free is also a DEX ability check.
The player can't decide that their character does wriggle free. They can decide that their character is going to try and wriggle free. The DM decides how that will be resolved.