Not sure what more info you need, but yes, it's in MP it is a problem. I use EDEN ofcourse to design the mission, and when I test it out in MP (only me as player though, and still within Eden), it is as stated earlier - won't move the marker when I disassemble/reassemble the tent.
I've tried all three tents.
I've tried the WeaponDisassembled, and I see I need the code to find the correct marker, find it and delete it. For that I guess I'm going to have to use allMapMarkers. To find the correct marker, I guess I have to use setVehicleVarName when assembling the tent so that I can easily find the correct on in allMapMarkers.
It's been such a long time since I've scripted, so I have a lot to re-learn.