Usually if a route's grade has not been confirmed, this is made clear by stating 'unconfirmed' when the route is reported otherwise there is nothing to stop outrageous claims being made (obvs not in this case). E.g. in the old Lancs guide, a new, unrepeated route had a '†' symbol after it to denote that the grade was unconfirmed.
To take the case of bouldering, there is not confirmed Font 9A...yet. So it would be a prudent if it was mentioned that they are unconfirmed rather than just taking the proposal at face value as it is just that, a proposal. Take 'No Kpote, graded 9A by Charles Albert but downgraded to Font 8C by a recent repeater
Post edited at 19:30