This is more of an animation thing than live action but I hate it whenever someone gets taken prisoner and they're allowed to keep any armor they're wearing along with misc. gear that they might have with their armor. Although they're (presumably) searched for and removed of any weapons and other useful items, it just looks stupid to see someone sitting in a cell all geared up and ready for action like they weren't prisoners.
On a related note, there's the old trope where a character, usually our hero, who has a special gizmo/doodad that gets taken from then when taken prisoner or losing it in a fight but later on are seen with it back in their possession although we' never see them recovering it and it seems like that there wasn't time to retrieve it either.