most times this original members might be escrows and you no what can happen when you mistakenly meet an identity thief to act as an escrow for you.
Members who act as escrow always should have positive trust ratings on their profiles, for confirmation it must be a rating of +2 or above, for them to handle trades. (Just my opinion)
There is no way the forum can prevent some one from using a name that has not been used before despite its close resemblance to existing name
No one has any trademark or hold on a particular name, it's about who used it first, and it's not illegal in my opinion.
Just that members should be very skeptical and guarded when entering trades.
For clarity the real name owner can leave a neutral trust in the account with a similar name, stating that it has no ties with them.