I assume that’s because they see them all day long so they are pretty good at spotting them in an X-ray. They don’t see weapons or actually threatening objects very often, or ever except for training.

You can bring frozen water through. Just drink the liquid before you actually get screened.

Once you drink half, refill it at a fountain (or lukewarm water from a bathroom sink if you can funnel it in) to have more cold water.

Many major airports (and many minor ones it seems) offer a way to refill empty bottles after the 'security' check. That's not really the point of my comment though.

The latest trick is to have ‘convenience’ warm water at the toilets after security, so you can buy water bottles at the shops.

I've never had problems asking restaurant bars inside the terminal for ice.

That will not fly in Europe. The size of empty bottle also needs to be smaller than a specified size.

If your bottle is empty it can be as big as you want. If you have anything with liquid in it (or semi liquids like toothpaste) the container must have a capacity of less than 100ml.

There are exceptions for medications and baby food.

Flew through France with a refillable bottle no problem. Where about a is it an issue? Want to make sure my expensive bottle isn’t donated to security.

Paris CDG and London LHR took empties a few months back.

Maybe I just got lucky? Flew out of cdg last month.

Where is it against policy? I recently brought frozen water through e.g. Malaga airport.

Well Coca Cola doesn’t make any money on Dasani or Smart Water if you slip on by!