Some people use rear wheel-on trainers, some take just the front wheel off for incline machines, others take just their rear wheel off, others still are on rollers with both wheels on.
Strava needs a selection for each indoor ride activity: rollers, wheel-on trainer, or wheel-off trainer.
I use a rear wheel-on trainer. Every ride is adding mileage to my rear tire, not my front, but Strava is recording it as mileage on my front tire too. The trainer can’t use brakes or I fly out the third floor window, but the brakes are gaining mileage too. Same for the front wheel which is just sitting there. Etc.
For people who remove their rear wheel for the trainer the cassette can also be saved from mileage recording.
For people on rollers, no change that I can think of is really needed from a regular outdoor ride.
It’s looking like a long cold snowy Chicago winter and the mileage difference between front and rear for me is growing quickly. If the component tracker is to have any relevance, this feature would be an elegant solution.