I'm guessing they're asking to have them work for vehicles. This really should be in Pimp Dreams if it's a suggestion.
I think someone mentioned pressure plates working now, but I haven't tested them since I use motion sensors, but if the OP says they aren't working, then the original person may be wrong or was using a mod or something. Or only certain ones work or only for certain vehicles. I haven't tested, so not sure.
In any case, pressure plates should work for vehicles. And it could be a nice feature to add a motion sensor option for vehicles so instead of just you or allies or zombies or players (I think those are the 4 options), you can also have a choice for vehicles so you could set it to only trigger for a vehicle. The downside with that is that it could stay triggered if a vehicle is in view even if you're not in it. Unless they make it so vehicles only works if a person is in/on it. Could definitely be useful to add.