A confiscation too far by Kent Police?

The BBC reports (Protest officers seized balloons) that some unusual items were confiscated from a power station protest group.  Supposedly items are meant to be confiscated to prevent offences being committed, but a FOI request reveals that along with the aforementioned balloons,

items taken included blankets, a walking stick, a clown outfit and soap.  [...]  A mountain bike, cycle helmets, bin bags and party poppers were also taken from protesters entering the camp site.

 The Kent Police assistant chief constable Allyn Thomas said:

"By seizing items which could be used to commit a crime we were able to ensure criminal acts were not carried out and more importantly no one was injured by some of the items which potentially could have been used to harm others."

Well, I'm not happy with the police deciding that everyday items are being carried with the intent of committing a crime (obviously knives and weapons are an exception), and indeed, what crime were they expecting to be committed using balloons, a mountain bike and cycle helmet, bin bags or party poppers?