I'm curious because there are many users with green trust with 40+ and are not in default trust
Trust score is not much important, esp. with accounts being bought and sold.
It is not correlated to being in default trust either. For example, shorena has a trust score of 13 (when viewed with default settings), but he is on default trust, and is much more trustworthy than most of the others who kind of got higher trust score incl. myself.
The content of the feedbacks is more important than the score itself. For example, some get a green trust just because they used an escrow who was in default trust, which doesn't actually mean anything if you are looking for trustworthiness.
Always use escrow.