Falcon Heavy and Roadsters: at least two respondents in this https://futurism.com/experts-elon-musk-roadster/ seem to think the aim is to put the Roadster in orbit around Mars. I don't think it's going close to Mars, just a heliocentric orbit out to near Mars' orbit.

Still, none of them mention the only legal issue I can think would matter: planetary protection - the obligation not to contaminate Mars with all the bugs on the car's tyres, etc.