I don't think this is necessarily a bad idea, but I do think that it's extremely premature--a couple of European scientists have come up with a plan for conservation parks on Mars.

I think that their concern here is vastly overblown:

"It is the right of every person to stand and stare across the beautiful barrenness and desolation of the Martian surface without having to endure the eyesore of pieces of crashed spacecraft scattered across the landscape," they write in the latest edition of Space Policy.

Mars is big. Mind bogglingly big. It has about as much surface area as the land of the earth. The likelihood that you'll see any traces of humanity over most of it for the next century or two is vanishingly small. They seem to be dramatically overestimating the amount of potential activity there, and by the time we get around to sending enough spacecraft for it to even start to be a potential problem, we won't be "crashing" them there. The notion of destroying a sufficient number of probes for them to become an eyesore anywhere one goes on Mars is ludicrous, logically and economically.

But he's not a total moonbat (or in this case, Marsbat):

But Cockell argues that if a planetary parks system were in place, it would free up the rest of the planet for exploitation and claim-staking, which might encourage these nations to sign up to the system.

Mars already is a de facto conservation park, in the sense that it's off limits to humans (for now).

Hey, maybe we can get Ray Bradbury to design a theme park on the red planet...