Just to pick up on a point, it is a legally enforciable requirement of BE's contract with the Dept of Education to provide schools transport that all vehicles are less than 20 years old and fitted with certified seat belts.  Further to this, it has been widely advertised in the last week in national press that from October 2011 it will be law that ALL buses used for the transport of school children (whether home to school, school to home, excursions, field trips, sports events etc) will now have to be fitted with certified seat belts.  A loop hole existed up to now where the buses operated by BE or contracted to them had to have seat belts but privately owned local school services or vehicles used by the school for other outings did not need belts.  Now any bus used in the state for the transport of school children for any purpose must be fitted with certified belts.

Here is a link to the RSA's press rerlease on the matter:
 http://www.rsa.ie/Utility/News/2011/New-Safety-Belt-requirements-for-Organised-transport-of-Children-on-private-Buses-/
The title is misleading in referring to "Private Buses" but this, I think refers to the fact that the majority of buses affected by this will be privately owned.  the third paragraph states:
"Organisations or individuals engaged in hiring or contracting bus services for the organised transport of children should ensure that the vehicle used is fitted with safety belts and that these safety belts meet the required standards."
Which brings BE into the fold.

What is interesting is that this legislation excludes the transport of children on a scheduled bus service open to the general public.  So a city bus on a general city service on whihc school children travel also is not required to adhere to this law.  That may be what covers DB and BE on certain services in Dublin and the major cities.