I wouldnt be so sure. In my days at checkin I perhaps had one person a month who would admit that their luggage was out of their sight for a while say between when they left their hotel/residence to the airport. Id simply ask them to have a quick look inside their luggage until they were absolutely satisfied that there was nothing out of the ordinary inside! Id hang onto their details and have everything ready to go (boarding passes, bag tags) and continue to pull other passengers from the line until said passenger was happy with their check and then I would send them on their merry way, no bull, no hassle and piece of mind for all!!!
Also when I worked at EI check in in the last 90's we had a mad question regarding if they had any new and unused electrical items in their luggage. It only happened once that a chap said he had, I cant remember what it was exactly but he said he had only just bought it and it looked kinda complicated. It threw me a little because it was something that happened so rarely that no one really seemed to know what to do so we simply rang airport police and they asked me to bring the guy over to a scanner and get it scanned to make sure there was nothing dodgy inside it. Once that was done all was fine and again, off he went and all were happy!!!!
Having said that, if you are clearly having a joke, YOU DESERVE THE RUBBER GLOVE TREATMENT!!! But if you are offering an honest answer then you should not be afraid of receiving a rude response!!!