But I think you miss the point Knold
, if 123.45 is not assigned for, say, air-to-air use, then it shouldn't be used for that. If the SAR service is assigned the frequency they can use it and are entitled to expect that they will not suffer interference from people abusing the frequency spectrum.
And just to confirm, it' not allowed to be used in the UK - see the NOTAM below
OTH : FROM 03/01/17 15:17 TO PERM B0148/03
E)FREQ 123.45MHZ NOT TO BE USED AS AN AIR TO AIR COMM CHANNEL WITHIN RANGE OF ANY VHF GROUND STATION IN UK FIRS