I finally remembered the other thing.
Sensor webs. Put 2 up, one within, say, 20 meters of the other. Nothing can be in between them or it won't work. If an enemy crosses between it, it alerts the deployer (if not the whole team) of the enemy presence, refering to the location as "<<playername>>'s SW1", which would give at the very least the deployer an idea where it is. Since it constantly refreshes, give a 2-5 second sound alert, or just make it appear in the text box. But better, yet, make it appear at the bottom of the screen. Placing a third would possibly make a sensor plane, and a 4th could possibly make a sensor area. Which would show the exact position of an enemy on the CC. If a person does not know the deployed position of a SW, then he can press the cc when he sees the alert, and for the timeframe the alert is up, a red area marks the location of the SW that had been tripped.
The reason i would like this put into effect is because i never knew exactly what was going in the base, and it annoys me. Where's the base alarm, and everything? I have to guess, and constantly check with my own eyes, or be surprised. THis would give me the ability to respond defensively to whatever happens. It would not tip the gameplay any, because, though small, they are still rather visible (like a camera), and any experienced person would know how to deal with it. (though SW destruction, unless both units are destroyed, does trigger alarm until they are destroyed). It would mostlly keep noobs on their toes.
That's pretty similar to the idea I posted a while back. You probably weren't on TW then, so here's the link:
http://www.tribalwar.com/forums/showthread.php?t=249644&highlight=type