bentarm

A pair at the club I play at has an agreement that their discards are "either reverse attitude or standard count, whichever partner needs to know". Is this agreement legal? They play together regularly, so it seems like they are more likely than their opponents to have an idea of what they think partner needs to know. If it is legal, are they under any sort of obligation to explain the sort of situation in which they think they would give count vs. attitude in any more detail?