I don't trust anybody I don't need to. Оncе a person shows they are extremely useful‚ and are willing to put in a lot of work, I assume a certain level of trust under the assumption that spies are lazy.
Then I typically test them by giving them enough stuff to tempt them to make a break for it early.
After they pass that test, I typically give them access to whatever they want. There is always a slight chance I get burned, but the suspicious ones usually reveal themselves in casual conversation.
The real threats at that level are usually not spies, but disgruntled loyal members that finally turn on you.
In any case, offer to do a ton of logistics. Оncе you put in 40 man hours worth of work‚ people ѕoftеn their guard. And some people that aren't quite so smart might not keep the alliance wallet in their personal wallet