Well I am one of the Drivers and I would have to agree the man should be sacked! Abuse of trust. However he has highlighted a problem that has been there during the 13 years I have been in catering.
It is imposable to be 100% safe with catering, the only way we shall ever be able to stop this happening for real would be to check every catering trolley as it boarded the aircraft as Kuwait Airways have done for many years.
I think the system works fine ATM as it works on looking for things out of place, now the catering driver was seen day in day out by BAA and was trusted, BAA would not be able to check every part of the vehicles, the driver has broken that trust and should be relived from duty. Because of this trust we shall never be safe from sleepers and just have to hope that the checks that are made on staff continue to work.
Just my 2 pennies worth.