This subject has been brought up before & by myself as well.
You would never be able to stop accidental comms on 121.5 we are all human & finger trouble has been known to take a plane directly to the crash site as well as incorrect R/T's.
What really shows a total lack of discipline at airline level ( I say Airline level or similar as most bug smashers wouldn't monitor 121.5) is the response one often hears from somebody accidentally using 121.5. Like for Eg ...................LT base this is XXX ..........a quick response.....'go ahead', then the poor chap or chapette proceeds to spill their guts on 121.5 much to the amuzment of others. These are the bozos/morons that need kick up the rear end!!!
Perhaps a different dedicated way of transmitting on 121.5 is the answer, much like a deliberate action event where as in it can't be done unless it's a totally different from day to day TX's procedures. Like a TX button not associated with ATC TX's
I know I often turn off the 2nd comm whilst in the terminal area as I might miss an important TX from ATC which does happen.
As for general chit chat Eg ride reports etc, (one guy asked anothet Co A/C to keep an eye out for a lost torch from a few days ago with numerous responses back & forth,all done on 121.5 !!!!) well you can imagine the slack environment in the cockpit when this sort of poor airmanship is wantingly displayed.
Bring back the strap at school, the school system has gone to pot!!!
Wmk2