In the case where the relationship breaks down before the undertaking ends (and they begin living separately): if the sponsored person goes on OW, this could be very bad for the now-single person on ODSP (the sponsor). I’m not 100% sure of this but I think it may be possible that the amount of the OW cheque gets deducted each month from the sponsor’s ODSP cheque. Or instead, there may be an overpayment flagged on the ODSP recipients file, which will have the same effect anyway (cheque amount gets lowered).