Arming took a step backwards in my opinion from FC1 to FC2/DCS! In FC1 you could pick what ever weapon you wanted to on any pylon before flight. Also, with Yoda's LEAVU mod we could in addition force payloads on a client.
Now in FC2/DCS we are stuck with default payload and list of pre-made payloads. You can customize them in the lua files, but it is a pain. On top of this, as the OP asks, there is no way to enforce a payload. The best you can do is file integrity check for the all the pre-made payloads.
You will never have a pre-made list of payloads that suits the needs of everyone. What would be sweet would be the option for a client to totally choose his payload with choice by pylon, as well as the option for a server to enforce payloads if wanted.
Perhaps we will get lucky and ED will redesign this aspect of the sim for MP.
Pehaps Haaku if you could trigger the destruction of the airport's comm tower you won't get the ground crew and won't be able to reload. In Blackshark this was a feature that never worked for me (would still get comms if the tower was destroyed), maybe it works in A-10C now.