While googling for a sanity check on the use of the word TYRO to indicate inexperienced pilot, I cam across this ancient thread:
MAYDAY MAYDAY require advice on the use of the word MAYDAY!
The OP says that their examiner insisted on prefixing their callsign with MAYDAY in subsequent comms after declaring a MAYDAY. I thought it worth pointing-out that is proper in marine procedures - effectively your callsign changes to MAYDAY Saucy Sue while your mayday is in effect, and all comms relating to that mayday are prefixed MAYDAY Saucy Sue. Although it eats time, it is very helpful, especially when someone else who has not heard the original call, comes onto the frequency - they can hear there is a MAYDAY underway so knows the keep quiet. In fact, a marine MAYDAY automatically imposes radio silence on all other stations.
Interesting difference, I can see why; almost all a/c comms is more urgent and more immediately safety related than conversations with the coastguard, so you have to keep some of the normal stuff going while dealing with a MAYDAY. But I like the principle.