Trust is not moderated, but trust spam with no intentions other than spamming is forbidden:
Trust spam isn't allowed. If I see anyone posting dozens of fake trust ratings (from one account or many alt accounts), I will delete all of their ratings
What's the best way to report this kind of spam? I want to report trust spam left by
Moseas79 on my profile:
19 trust left, 81 lines each. Total: 1,539 lines of fake trust 
2,430 lines of trust spam nowEdit:
Also
Buzzlieve1992, who left trust spam to other users (and probably to me too very soon as I'm leaving negative trust to him now).
Also, I think there should be some limits regarding trust, something like for example:
- Not more than 1 trust left on an account per account and IP per day (I know this can be fouled, but it could help a little at least). At the moment it seems newbies have much more limits on posts and PMs than on leaving trust
- Not more than 300 chars per feedback at most. Not more than 5 new lines. If more is required, a post on Reputation can be opened and linked on the reference
Trust should be informative and readable, not intrusive.
While less annoying than Moseas79, several other users intentionally add extra blank lines or leave spammy "previous versions" of left trust with repeated information with the sole intention of making it longer and use more real estate, like
TheButterZone or
Engg.Chaks did on my profile.