I used to routinely fly with the transponder firmly in the "off" position, saved the batteries.
Only reason it was fitted was to allow crossing of a recently imposed TMZ, for which it was switched on, then switched off once across.
Now, i'f I'm flying my glider along with the mode S on (as I now have to, when I remember to take it off grnd) and you are flying your spamcan along, monitoring (what do you actually do in those things en-route to your next cup of coffee/ bacon roll?)
What do you have to tell you where I am ?
Up here in the frozen North, there are large areas where spamcans fly not covered by radar (pesky hills getting in the way)
And when I'm operating at sensible alts, there are NO spamcans.
Why do you not have Flarm fitted ?