Publishing the source wouldn't have hurt his income and would have prevented some bad advertising.
Incidentally, I had to explain to my wife why I had to jump on the computer immediately when getting home from work and I never thought I would see the day when I would be chastised by my wife over a GPL violation. :)
The DOSBox folks and the Google engineers working on Native Client are geniuses. By comparison, my C++ skills are only slightly more sophisticated than the monkeys you see throwing poo at the zoo. :)
Take a look at what I hacked together. I had a lot of fun working on it over the last couple of weeks.
(Incidentally anyone with nerdy kids should check out the Suprer Solvers games ASAP)