Yeah it's only legal if you have "run flat tyres" to not have a spare - will say on the tyre (usually OEM on BMW, Audi, Mercedes and the like)
Touge Boy the tyre mouse goo is only good to get you to where your going. It's only a temporary "fix" until your tyre can be repaired/replaced. For anything bigger than a pin prick, or if you have a hole on the sidewall it's pretty much useless! Especiallly on something as heavy as a F100. Only really practical on motorcycles.