I always forget to be honest, and have never got a bollocking yet
Some places (Bournemouth) have a "3 strikes and you're out" rule. Caught 3 times, and you're banned.
I always forget there and have never been bollocked
I suspect it is there because if an accident happens they can say "you should have been wearing your high vis jacket, so you can't sue us".
Anway, a loud Hawaiian shirt probably counts as a high vis jacket