Also, in case someone jumps the first time to DT1 or DT2 it might make sense to send out an automatic email to this member and explain him the implications. There is no info otherwise without checking. It would give the user time to check the trust before a fight occurs about settings or ratings other members don't like.
I would also like to support this feature. Most users are not intentionally doing "trust abuse" when they've set an uncommon trust list or left lots of feedbacks without reference, in most cases the users on their trust list are their trading partners and that's why they've left each other also a positive feedback. That's totally fine but might change if the are DT.
And only a few users are checking the new DT list every month so most of the new members don't know that they are new on DT without notification.
The problem won't get less important in the future when DT expands every month...