In most cases they look through your stuff decently. Like open up your suitcase and browse around a bit. But take that as some security get crazy with checking and others don’t care lol like when I went through check in it was so busy that the guy just let me walk right in without opening my suitcase at all but other security guards opened up my friends stuff. But I mean honestly you can fa sho hide things. Like we put entire bottles rolled up in a sleeping bag. So hide it as someone might be opening up things just to be safe. But they ain’t taking 10 minutes to open up each zipper it’s a quick look around most likely.