> Depending on local laws, stealing a car may not actually be theft if the defendent can prove they intended to return it before the owner got home from work

I doubt there's even one place where the law works like that.

> I doubt there's even one place where the law works like that.

In a lot of places, that's how it works. A key element of theft is the intent to permanently deprive someone of property.

This is why joyriding isn't classified as auto theft and is instead a lesser offense. It's because joyriding is an intent to temporarily deprive, while GTA is an intent to permanently deprive.

In some jxns (the UK is one), there is a tort called trespass to goods, and an example of this would be "stealing" someone's property to deliver to another location for them to use there. The tort of conversion is similar: interference with someone's property right to treat it as your own (silent as to length of time).