Intetesting hypothesis, indeed. I’m cycling approx. 1/2 hour each (working) day.
After I had the display exchanged I started carrying my phone in a Feuerwear Mitch 10 belt pouch whixh @vowi researched in this thread:
Cases and screen protectors for Fairphone 2 (FP2) (or: Which fits better: Feuerwear Mitch 6 or 10?)