It's one of the restrictions on PMs, it's to stop people sharing information privately instead of on the open forum for the benefit of all.
33 Access to sending Private Messages and the visibility of Members Post history have different criteria to be gained. The criteria will not be made public. Anyone attempting to circumvent the PM criteria by requesting PM’s may receive a ban.
Yea, thanks for that and I understand the point made and was also aware of Rule 33 as you point out.
It's not often I PM anyone off the forum but sometimes the subject matter isn't really for the open forum if I do.
In this case I was asked by PM a question about a particular SP, she reads UKP and doesn't particularly like us

And would fuck me up for any future meets, if it was asked on the open forum I would have had reply by PM.
It's frustrating, but get the point you make and thanks for the info