thumbturn

Hi. Some time ago, a joiner fitted a new (primed) bathroom door and a thumbturn for privacy - probably Howdens. I need to paint the door (with acrylic water-based?). I have not removed this type of privacy knob before - only the the type that is integral with the handle.. I have slackened...

Would you worry about putting a thumb-turn cylinder in a sliding patio door lock? In theory, someone could smash the double-glazing, but how much risk do you think it is? Before you ask, I would only consider a decent anti-snap cylinder.