got my 1991 BRG late last year

The main reason for this has been the security of the hardtop parked in
town while I am at work.
But as I was driving over the hill (Masterton to Wellington) last night it
was such a beautiful night, I wish I'd taken the hardtop off. Of course
it had nothing to do with the 3 other MX5s I saw cruising along without
hardtops.
So this is directed to those dedicated topdowners/softtoppers ...
How often do people's soft-tops get vandalised/slashed/knifed etc? Is it
a real problem? Or no more than people keying cars?
How do insurance companies react to the damaged tops? What about repeated
cases of vandalism? Specifically thinking about AA Insurance here.
Does anyone haev any experience with problems parking at the Stadium, or
the Clifton Terrace carparks? What about in the city centre on
Friday/Saturday nights - any safe places to park - any bad places.
Many thanks for you thoughts,
Ian