Most people never realized an even higher level of radar metagame in Mech4.
Yes there was the whole Bap/Ecm. And you could shutdown somewhere and ambush.
But something most people didn't take advantage of was that if you shutdown active you could pick up mechs on your radar from 800m (or so ... its been awhile). It wasn't full radar. You would only get the image of the mech, but not the location on the map. But it at least let you know that there was a mech near by.
If you shutdown passive, you would only pick them up from 200m (or so). So if you had two mechs shut down, one while active and the other while passive, you would not only know when they got within 800m, but also when they got real close at 200m. This was extremely useful for ambushing the enemy team, but also catching annoying harassing mechs off guard. It was also useful for recon mechs, since they could keep an eye on enemy teams unseen even if the other team had an active ecm/bap mechs looking for you (if you were good at it..its hard).
This simple feature added huge depth to radar warfare.