I don't even want to give them a chance to open the door! What I really hate is when I am keeping the door shut with my hand and they are still trying to force it open which then results in me yelling "I'm in here!" while trying to keep door shut and not lose my aim and have accidental spillage while floating all at once. HATE that.
I know what you mean, I hate having to hold the door to keep it shut. Going to the bathroom shouldn't be a stressful experience.