How long does a developer/publisher have to not give a notice of discontinuation before software enters that grey area of Abandonware?
Personally I would be inclined to say not to crack it. You never know if the development is in some form of hibernation. However, and i don't condone this either, if someone where to stumble upon the key through some form of search and that key happened to get to the program and it magically worked then I suppose, so long as that person keeps it to themselves and we enever know, it could be alright.