The person fiddling benefits is committing a criminal act. What is Kate Middleton doing that is illegal?
It's a fascinating conundrum, however, that evokes the thorny questions of Society's norms, legality and statutes of limitations. The Royal family itself is in power (and allowed to spend a lot of money) because their ancestors committed murder, mayhem, larceny and multiple abuses against our ancestors and got away with it, simply because they were the bigger bullies. Now, they're revered by the likes of the DFM, but one does tend to wonder about relevance and responsibility.
The issue that brings this into focus is the Age of Consent in countries around the world, a breach of which criminalises one of the individuals concerned. What is legal in some countries at 14, for instance, is termed rape or abuse in others until the age of 18. In Shakespeare's Romeo and Juliet, for instance, Juliet was 13 on her 'wedding' day, and that wasn't unusual, particularly in Royal Families. In the 19th and 20th Centuries, familial conjugation amongst the Royals was common, and it's only relatively recently things have changed. That's the nub of it, too; as times change, what's legal and acceptable also changes. I do sometimes wonder if there's such a thing as Right and Wrong, objectively.
B2R was legitimately examining the DFM's obsession with what that egregious rag calls the 'benefits class' based on financial disparities, while ignoring far more significant financial disparities that might be occurring elsewhere. In fact, the current trip is largely paid for as the couple themselves are actually employed by the Government (though I doubt there's a detailed job description :-) as ambassadors and envoys and - in that sense - they do a good job. I've been thinking for some time that the one thing that might possibly swing the outcome of the Scottish independent vote might be a major royal visit by 'er Maj. She still has a bit of clout North of the border, not to mention the odd castle or two...