We already find/track orbital debris in LEO, so I'd imagine finding a satellite should be doable by interested parties, unless there's some new tech on there that makes detection significantly harder.
That's not really surprising; I'd imagine most long-term satellites carry thrusters and at least some amount of fuel for stationkeeping, especially in geostationary orbit. It'd definitely make it much more difficult to track, unless you keep something pointed at it 24/7 so you notice the change in velocity.
And nice find with the SBIR competition! Does seem to point towards satellites being much more difficult to track than I thought if they're constantly moving.