As Schneier points out this is as stupid as locking the fire alarm boxes (as they were in Chicago prior to 1870--guess what happened in 1871). Bloomberg wants people to have a license before they "possess or deploy" biological, chemical, or radiological detectors. This would be to prevent false alarms, just like the locked fire alarms.

You already knew Bloomberg wants to get rid of guns and I'm thinking he is going about all this the wrong way. Rather than enumerating the objects you are not allowed to have he should make a list of the items his subjects are allowed to possess. I'm thinking that ultimately the second list would be shorter and easier to maintain than the first.

Update: Further confirmation my approach would be simpler arrives via Uncle with this story:

And in what appeared to be a direct shot at his predecessor, Republican presidential candidate Rudy Giuliani, Bloomberg described the city government he inherited when he took office in 2002 as "insular and provincial and married to the conventional."

At first glance I thought he said, "married to the constitution". But of course that wouldn't make sense because he was talking about Guiliani.

He also announced that the city is challenging the private sector to create a portable device for police officers to carry that will analyze DNA right at a crime scene. A monetary prize will go to whoever comes up with the technology, he said.

Bloomberg also outlined two law enforcement initiatives that would need the state Legislature's approval: a proposal to collect DNA from suspects upon arrest and another to make it easier to trace bullets used in crimes.