Thank you. I apologize that I did not see your response before signing off for the evening.
A month to month tenant can be asked to leave at any time, as long as the landlord gives at least one full rental period's notice. This is also true of changing any of the lease terms. That's what the notice you received is, and that means it is valid. The landlord is also allowed to serve a notice of a rent increase at any time, and it'll take place after one full rental period elapses (meaning, any notice given in mid-July is valid September 1; any notice given August 1 is also valid September 1). So, yes, he does have a right to do that. Your option as the tenant, if you'd prefer not to tag and register all vehicles on your property, is to give 30 days notice that you'll be leaving and to move.
You should be aware that the landlord's request is not that uncommon. Many homeowners, apartments, condos, and HOAs require that all vehicles on the premises be tagged. And so do many local ordinances. You could have trouble finding a landlord who is OK with unregistered or untagged vehicles being parked in the driveway or on the public street in front of the house. If the notice from your landlord is reflecting a town or county requirement, moving won't help that. You may want to check your local ordinances to see if there's anything about unregistered vehicles being parked in driveways or on public streets. For example, look at these regulations in Fairfax county: www.fairfaxcounty.gov/fcdot/parking/parking_restrictions.htm
If you have any questions or concerns about my response, please reply WITHOUT RATING. It's important that you are 100% satisfied with my courtesy and professionalism. Otherwise, please rate my service positively so I am paid for the time I spend answering questions. If you are on a mobile device, you may need to scroll to the right. There is no charge for follow-up questions. Thank you.