Well, in a world of philosophical theories, maybe there can be a conflict. Maybe there are angels or were unicorns too. But I don't see a conflict if one person on probation claims another one with the same PO violated them. His remedy, if any, is to hire an attorney to keep from being violated if the PO brings the matter to a judge, but it's an uphill battle.
The standard conditions used by a lot of probation departments might have prohibited these two probationees from hanging out together to begin with, as probationees are not supposed to consort with disreputable people or known criminals.
Creative attempt at a defense, though.
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