...As far as the halfwits at customs they seem to have a really poor grasp of the law, they seize and hope you wont contest it in court. ...
I can't believe that they are not operating on 'instruction' from government to seize as much as possible. Doesn't have to be formal instruction.
Legitimately seized or not, every one will get added to a statistic that can be used to prove whatever point they want when it's useful.
Maybe I'm paranoid, but I really don't trust our leadership (any of them) in the slightest.
It could be just a case of not wanting to be found to have let something slip through that should have been caught, and given there is no come-back on them for seizing anything, that's the easy way.
I would still bet money on the former though.