[Kaoru's robot knowledge = 0, so that makes about as much sense as anything else could...]

I suppose so... It could have been that, or it might have been an item that allowed for them to bypass Miss Sto Helit's attention, or perhaps something that triggered the alarm early, or even an item that could have been used to bribe an accomplice. Just about anything could be in there, and without the actual item in hand, the speculation is endless.