People who are "accepted" by the owner of the forum should not be in any way promoted and be able to tag other people's profiles.
What matters now is not how many transactions the account is involved in or how many people left a trust rating but if these people are among the privileged.
If you have a better solution please speak up. As it is the current system is the most stable that we have had. Find a plan for forum trust that can't be exploited, or has a lower risk of being exploited, and I'm sure it will be adopted.
Every system can be exploited, just like the current one is. What I'd propose is:
Remove the default trust and make all comments equal. Rate the profile by the number of positive/negative votes.
Allow only 1 vote per account and don't allow newbies and jr. members to leave comments to prevent spam.
What I find strange at the moment are people leaving multiple trust ratings with the same purpose. Why doesn't the staff ban trust spammers or allow only 1 rating per person?