It seems that most view the inflight PAN or MAYDAY to have an automatic connection to ground services. Where some of you operate that may well be the case. While anyone can declare a PAN or MAYDAY on behalf of someone else, down here it is the pilots' responsibility, if they have normal comms, to request what they require on arrival ie Local Standby or Full Emergency status.
What happens in the air is NOT necessarily relevant to what I need on the ground. Eg, if I have lost cabin pressure (no mechanical damage) and require an emergency descent I would need immediate assistance ie=MAYDAY. Once I was down to 10,000 feet and may still want to land ASAP I would down grade to a PAN, or cancel Mayday, but not necessarily need any added ground assistance. To view the air situation and the on ground requirements as two separate entities will provide the best outcome I believe -having had some recent experience (two shutdowns) in this area.