When you load some bricks in your server and you want to add on to your friends build a little, it says BL_ID 1337 does not trust you enough, and you have to wait for him/her to join. BL_ID Trust would trust them from their BL_ID so you can build on your friends build and they don't have to join for you to do so.
Basically, you want to bypass the trust system. This idea is horrifying, as it will allow people to simply modify their own trust list to obtain trust on other peoples bricks without the builders actual approval. Noobs find it harder to understand save files than trust lists. If you allow a simple addition to their trust list to allow editing other peoples bricks, then there will be a huge problem with stolen builds.
The trust system works by checking two player's trust to be sure they trust each other. If that doesn't go through, someone may distrust but can still destroy their build, edit it, steal it.