a r/s cannot happen when a stock is caveat emptor.
According to whom? Caveat Emptor is something OTC Markets dreamed up. OTC Markets is not a regulator. If an OTC company wants to do a reverse split, it submits a corporate action request to FINRA.
See "deficiency determinations" here. Those are the reasons FINRA can deny a corporate action. "Caveat Emptor status at OTC Markets is not one of them.