Not that I am aware of, however, you can report the specific player to the WGT staff. I am sure they keep records of friend requests and such so they can see the abuse.
On the other hand, I had the same issue with another person doing the same thing. I just refused to respond to the invites. Eventually the person just gave up.
Your call, but personally, I would report the issue to WGT staff.
Yokosaki
MGA President