Originally Posted by
Easy Street
Anything squawking Mode S is being tracked by the avgeek network though multilateration (MLAT), it's just that the big commercial sites like FR24 filter out military MLAT-only tracks. If you go to the enthusiast-run
ADSB Exchange you'll see Typhoons, F35s and F15s doing their thing, at least until they get far enough from civilisation that they can no longer be triangulated. Squawking 3/C only is a workaround, at potential detriment to ATC/C2 and to TCAS performance on any aircraft which may come into conflict.
And that's why my fleet never squawks ModeS. Mode 3/C for domestic phases of flight only (obviously not during a conflict - for the OP) then tactical modes only. You won't be seeing them on ADSB Exchange thankfully!