Bmi's treatment of UM's is appalling. My other half works at LHR for SQ and they had an 8, yes 8 year old child that came in with Bmi that was left to make her own way from T1 to T3 to make the SQ flight with her bags because of Bmi's policy of paying for UM's and a payment had not been made for this child, so Bmi left her to her own devices. It happens regularly too from what I hear from friends at other airlines.
This also happens going the other way too. The airline inbound escorts the UM over to Bmi, who then refuse to accept responsibility for them as no payment has been made, and as they are at a transit point, the inbound airline then looses one of their staff in having to look after the child until the Bmi flight is ready to depart.
Truly appaling treatment if you ask me.