On Wed, 20 Apr 2011 11:48:38 +0200, Martin wrote:

AND of course have legal right to issue fines

You are parked on private land.
You agree to the published terms and conditions when you park on said
private land.
It's not a "fine" it is charge as laid down in the terms and
conditions of parking on the private land.
If you don't wish to accept the terms and conditions don't park on
the private land covered by those terms and conditions.

Simples. B-)

--
Cheers
Dave.