I know that sometimes there is a real scrum at security, and that it can be easy to lose sight of your stuff for a couple of minutes - especially if you are juggling/herding children too.
However, security willnot inspect something without knowing who the owner is/if the owner is present. there are many reasons for this.
Yes, if there is a queue they will "help" by taking you stuff/organising trays - both at the beginning and the end. that is not inspecting, though, and if the buttons came undone during this process then they must have been pretty close to coming undone anyway.
if they inpsected it properly, ie saw something on xray that needed closer inspection, or couldn't see properly on xray so wanted to open it up, etc they will ask whose it is, and usually take it to another area so as not to hold up the queue.
I always get my stuff inpsected (must have a dodgy face
) - usually because we are carrying above-the-limit liquids for dd1 (medical exemption). they may well have started inspecting by the time I have got through the walky bit with 2 dc, but they always keep an eye ut, and ask who it belongs to etc. they need to know this in case there IS anything dodgy about it.