Glastonbury 2011: Legal highs and lows

Yesterday, Micheal Eavis was bristly. Well, he's always bristly, what with the beard and all, but mainly he was bristly about the idea of testing Glasto waste water to see what was in it, drug wise.

Today, festival organisers are busily co-operating with police testing produce on sale in the site to see what's in it, drug-wise:

Police spokesman Paul Bunt said: "Because there are so many new drugs, we know very little about them."
[...]
He said it was "essential" festival organizers co-operate with the project, adding there were a number of legal high shops on the Glastonbury site.

The BBC report on this testing of legal highs doesn't quite answer all the questions it raises:

Police at Glastonbury have set up an off-site lab to test "legal highs" seized at the festival.

It comes after a rise in unidentified drugs found at large music events across the UK.

The Forensic Early Warning System allows government scientists to analyse and detect traces of potentially harmful and illegal substances.

Police remove drugs seized at Glastonbury to a laboratory located several miles off site where they are tested, identified and catalogued.

What this doesn't explain is by what right the police are "seizing" substances that, by their own admission, they can't identify.

Yes, there needs to be something done to stop dubious crap being sold in shiny wraps, but letting police look at something, go "dunno what that is" and seize it seems to be an odd process to follow.

[Bunt] said shop owners had worked with police to narrow down the range of merchandise they sold to make sure their products did not contain illegal or harmful substances.

It was a "condition of their entry", he added.

So if the sellers are co-operating, is it just the word "seize" is wrong? It sounds as if the people selling this stuff are as keen to know what it is they're selling as the police are, and are co-operating. Which might be a positive, collaborative way of working. So why frame it as if there's bad guys being thwarted here?

[Part of Glastonbury 2011 full coverage]