agree it's hit and miss.
i was back in London last weekend for literally just 2 days and only took hand luggage (a friend in london had sourced with all those illegal items like toothpaste, shampoo and deo).
i didnt even realise it but of course i had taken the CW amenities bag with me and put it into my bag and i guess it has the usual mini items of liquid. no word at all when i went through T5 security 2 days later with it (as said, not even fully remembering i had them). about 18 months ago, i was treated like a criminal at MAN when arriving back from JFK (gone are the days) and connecting onto a domestic flight (also, gone are the days of BA offering that) and not 'declaring' my CW amenity kit from the inbound flight.
and - just to finish off this mini rant - i bought 2 newspapers landside at T5. the lady told me i'd get a free bottle of water so i took it (in full knowledge that 2 mins later i was going to pass through security, i.e. would have to get rid of it beforehand). wasnt overly thirsty but wasnt going to pass a free bottle (sealed). it was impossible to find either anyother landside pax or any of the staff to take a free, sealed bottle of water off me! and i looked quite respectable on that day. so ended up throwing it into the bin as the security lady was giving me the 'if you suggest one more time that i take your sealed, fresh and still chilled bottle of water of you for my personal use, i'll have you arrested' look.
wasteful shame - should have probably just left it in the shop but then the daily telegraph would have 'gained' it.......