Indeed, security in T5 can be rather amusing to watch (and annoying as well).
Just last week I witnessed a passenger demanding to speak to the manager of "British Airlines" as she had been asked to remove her laptop from her bag and therefore thought she was suspected of something. The poor chap kept explaining to her everyone had to do it but she felt it was only her. I wish I'd seen the outcome of this!
Conversely, I have also been made to do some extra ordinary ridiculous things before. I once took through an empty plastic bottle but not in a clear bag! When the agent told me I must put every item in a clear bag (!!!) I politely said he was mistaken. I was put to one side, had to wait 30 minute for a scan and full check of everything. They also swabbed my belongings. Security at airports is the one place you can't really argue with them!
I think the highlight must have been a story my mother told me from about five years ago. She was behind this very well to do Russian family and they put their bags through the X-ray machine. Inside one of the bags was their pet dog!