Can a shower hose be taken on planes worldwide without hassle?

My experience:

• The US, the TSA agents are lazy time-servers but fairly literal-minded. If it isn't on the sign (which a shower hose isn't), they aren't going to take it from you.
• The Third World, guards are mostly bored teenagers who will frisk you but won't do anything that risks creating paperwork for themselves unless you actually brandish a weapon.
• The UK, guards are resentful proles, looking to screw over anyone with the means to travel internationally, but the X-ray process is mostly automated and the worst they can do is hold you up for a few minutes.

These are only my observations, and perhaps a little over-generalized, but I wouldn't worry about it too much.

From reading some reviews on the amazon link, I think the hose and whole shower head is plastic, even the "chrome" version. If so, there should be no problems with it being x-rayed through security. Even if it were metal, and especially if you had the original package it should be fairly easy to examine (could even blow air through the hose to show it's empty).

I'll paste a few relevant clips from some of the reviews here:

"the cord felt cheap (rubber)."
"the rubber hose does not straighten"
"buy plastic plumbing equipment?"
"The shower head itself is so lightweight I'm afraid it will crack if I drop it and it weighs practically nothing. It is made of a very light weight cheap plastic"

There are a lot more positive reviews than negative, I owned a similar shower head & hose that was all plastic, though it looked like shiny chrome. It worked great for a long time, despite some negative reviews too. And I've read sometimes people receive different items from different amazon sellers, even when buying the supposedly exact same item...

I suspect it may be a problem. The hose in your example may not allow X-rays to penetrate. And this may lead the security agents to wonder if it conceals a forbidden item.

Q: Can a shower hose be taken on planes worldwide without hassle?

Since it is not possible to answer for every terminal entrance operator in the world, the best you'll get here is advice based on experience.

While a hand-held shower might seem unusual on it's own, it's probably not that unusual among thing people take on an airplane, all totally harmless.

Using US/CA/UK as the standard, a hand-held shower is not prohibited. But if the screener doesn't recognize it or you just picked the wrong lane, you might get some additional careening. If this happens, 99%, it'll just be an verification of what it is and a swab test.

To reduce chances of this happening, perhaps chose a plastic model which would have less substance on the belt scanner.

Also note, in the US/CA/UK, if you declare this a medical device, especially if your friend has a visible condition, you back them into a corner making it much more difficult for them to refuse it, but only do this as a last resort.

Q: Is there going to be difference to the security if it's already used? Or does it have to be packaged?

It's probably better if it's unpackaged since it would make it easier to swab if it gets to that.