Really? Another Miata thread....

[Senor_Taylor]

This is what I do. Never leave anything of value in there and leave the doors unlocked with the soft top up.

Hard top, lock the doors.

No one wants to steal a modern car, in your case, as it's too hard without the keys, but if they see something they want, it's a broken window or a cut top to get to it. Sure, steal my $50 head unit, but don't ruin my car in the process.

But in the end, I lock the doors often, but there's no rhyme or reason I do. I just feel like it some times. For you it should be easy because your passenger side should have a power lock if you don't have a key fob.