The windows could have been cleaned at Kingswear. Was the graffiti mentioned on board by staff or, ignored?
I'd imagine that a glass scraper (something like a handle fitted with a Stanley-Knife type blade, edge out) would get rid of most of it fairly quickly. Glass, on the whole, is quite forgiving in that.
The graffiti I saw was extensive, in that blobby-letter style you see on US and European suburban stock. Clearly the work of multiple taggers using multiple paints. Scraping the windows would have taken a fair while. I've found one shot, though I saw clearer ones on Twitter.
I think it safe to assume that such solutions would have been considered and then ruled out?
Apparently there are shops that get major income from knowingly selling paint to people who will use it in this way. Do we need to find ways to restrict the sale of spray paints?
A Homebase near where I used to stay had an agreement in place with the local Cop Shop not to sell aerosols. The 'Edinburgh Bargain Store' round the corner had no such qualms, and you could buy any shade of paint you could imagine. In Edinburgh, likewise, there used to be a sort of official graffiti shop of sorts down at the bottom of the Pleasance. I don't know what its intended purpose was, but it sold lurid aerosols and the interior was covered in graffiti.
The flip-side is that I recently used a set of Halfords aerosols (primer, colour and clear coat) and couldn't get the stuff to dry hard at all. Regulations increasingly limit the solvents and potency of aerosol paints, so it seems sadly ironic that the stuff sticks so tightly to trains and buildings, when it can barely perform the job it is meant to do.
My harshest wake-up call was riding a graffiti-strewn train through miles of graffiti-strewn concrete jungle through the outskirts of Paris. It doesn't inspire any great confidence that you are in a safe environment. My sympathies are with those on the on the tour who paid a lot of money to then squint at the view through graffiti'd windows. I also don't relish the job of whoever has to clean the coaches and the 47 up.