Some reporter published a transcript of a then-legal intercept of a cell phone call between Dukakoids. The gist of it was
that they were going to have the limo drop Dukakis off a block away from some appearance, and have him walk to it from there.
Obviously an appearance more than a block away from the Governor's office, but not so many blocks away that it
can't be walked in reasonable fashion.
I don't think it's something the Royals do for effect though- Kemble to Paddington's a far longer journey then you'd make for apperances sake, getting on for 100 miles which for Britain is pretty considerable. Frankly, if she wanted to she could always take the helicopter or be chaufferred in. Instead, she'll turn up in 1st class with a couple of police officers and sit around like anyone else; as I say, I'm rather surprised that Charles doesn't do the same already.
As a rule the Royals are far less profligate with these things then politicans. Margaret Beckett charters a jet to and from her constituency at taxpayer's expense, and that's just to Derby which is quite frankly insane. I think a lot of it is a generation thing; have a look around the Royal Yacht Britannia up at Leith and it's a really tatty old thing, the Queen et al obviously retaining the thrifty post-war mentality. I always think it's rather endearing.