W210 Trunk opened on its own...random occurrence or sign of future problem?

[nhdoc]

So today I am sitting in a parking lot, in my '98 E300 with the tranny in drive waiting for someone to come out of a building when I hear what sounds like my trunk lock release and sure enough the trunk pops open!

I know I didn't touch the release switch on the console and the remote was in the ignition so the release was tripped on its own...I didn't even think the trunk was supposed to open if the car was in drive (not sure about that though).

Anyway...I am thinking that maybe I was in an area with lots of stray RF signals (it was an industrial/office park) and so perhaps an alarm or security system just hit the right frequency/signal to tell the trunk to open. Has anyone experienced this? It's never happened before in my 3 years of ownership so I am not getting too worked up but I'd hate to have it happen while I was driving down the turnpike!