Sorry Dodgy not the MPBA, but the UKRCC, and I think you will find the requirement for the stickers comes from the EU....
Um... the requirement for stickers is certainly an EU directive. What I was trying to stress (paraphrasing the Wiki article) was:
1 - The EU has instituted a marking scheme which does not provide a high degree of assurance that the marked item is compliant.
2 - This marking scheme has the benefit of being immediately visible, so there is a demand for it from the marketplace (purchasers, clubs, and lower-level regulatory groups like the MPBA).
3 - The net result is that many items are provided with stickers, but there is no assurance that the items either need stickers, or comply with appropriate regulations if they do in fact need them.
This applies across the board to all CE markings. In the case of radio transmitters it is certainly true that they need to comply with a variety of regulations, and carry stickers. What I wanted to indicate was that while a scheme to ensure proper technical and safety compliance seems like a good idea, and is generally thought to be a good idea by the consumers, in practice the scheme is not foolproof, and may become a meaningless icon, kept alive by customer demand rather than practical benefit.
Mind you, there are a lot of similar instances in commerce. All bottles of alcoholic drinks carry an assertion that they are of a particular strength, and all packets of cigarettes carry an assertion that duty has been paid on them, so I suppose it keeps someone happy...