Brimstone wrote:

People have been leaving their property on underground trains since 1863.
The announcements you refer to have only been in use for ten years or so.
Hardly knee-jerk.

I was calling it knee-jerk because I have seen no evidence that it helps,
it's just a predictable way of trying to solve the problem which may or
may not be effective.

(But I do agree they are a serious pain.)

I would be willing to put up with the pain if there were evidence they
actually worked. Which would actually be easy to prove, IMHO, but it
would require LU's help to do so.
--
Michael Hoffman