Quite recently, I have seen access=yes appear on National Roads (highway=trunk). I do not know what makes that tag necessary, because I thought that access to such roads is assumed to be all-purpose.
I ask this because Osmose has been whining about “Overly permissive access” (source).
I would agree this is unnecessary redundant data.
However, Osmose is also incorrect in highlighting this as an error or warning, highway=trunk in the UK (and AFAIK) Ireland does not imply ANY restrictions on any mode of transport. In other countries, notably Germany & Poland I know highway=trunk is only used for roads which, for instance, don’t allow pedestrians and bicycles.