Originally Posted by Doge

This is the primary reason I have seen for a PM.

Coaches are not often direct.
"Do you have a PM?" vs "Get a PM so I can see the data.". Should be followed with information about how it will be shared.
Are they the coach, or are they scouting you. Do they coach your competitors and share information?

At a certain level, and places this is a significant thing. Uploaded power data tells others where you are at and can be used by them to improve your training, or help someone else beat you.