Do VOLUNTEER meter maids have th authority to issue parking tickets?

I know that they DO issue parking tickets... but if they are volunteer and don't actually have a badge... could one fight the ticket, claiming that the volunteer officer doesn't have the authority to issue the ticket in the first place?

If the city has empowered them to do so.

There are VOLUNTEER police officers, normally called Reserve or some other term. If sworn they have the powers of arrest, carry the gun and so on.

For example in TN volunteer or part time police officers do not have to be POST Certified merely sworn in. ** Reminds me of Gobber on the Andy Griffith show raising his hand to be sworn in.

So if they are issuing tickets then it appeas your state and your city allows them to do so.

Their paid status has nothing to do with their power or authority, their assigned position and the state and city law regarding it is all that matters.