Conditional Custom Attribute

I have an event attribute #_ATT{Parking} that I use on single event pages. Is there a way I could make it show conditionally only if an option was selected (not left on default)? I tried {has_Parking} but that just hid the attribute regardless of which option was chosen.

#_ATT{Parking}{Select|Free On-Site Parking Available|Limited Free On-Site Parking|No Free Parking Available}

I also have a similar attribute, but it is a fill-in-the-blank and I’d like to do the same there.