I would do this for free for Blitz as when they are better known by the world I have a greater chance that I can still use BlitzMax over 10 years.
I can't believe BRL would have any problems with this, unless you plastered "Made with BlitzMax" all over the latest virus you've just made.
I think this would be a very effective way of raising awareness particularly if someone like GreyAlien did this on his games.