I think it’s as much a safety thing in case people got on while it was moving, I’d say surely they noticed but they’re often oblivious to anything other than their phone
At peak times it is likely to upset people as well but the notice wasn’t particularly clear.
Seen several high level guys ( and girls ) doing more 4/800 m intervals than long steady 5-8 mile runs it seems these days
Lots train at altitude/ heat/ stressful conditions for obvious reasons I think Tommy fumbles did a 49?Min 10 k not long ago although he has gone faster so his stations must have been rapid to get a sub hour time .. he’s a pro athlete I guess