Of course, it's early days so there are no facts apart from the fact that objects have been found that could be radioactive. It'll probably turn out to be something harmless, like a few smoke alarms or something.
You might consider why, in numerous policy documents and in first responder training, it is very clearly set out that a CBRN response must be limited to deliberate and malicious acts designed to cause harm or fear amongst a population by using or threatening to use CBRN materials and substances.
Accidental and conventional chemical incidents/spillages and radiological events are not subject to CBRN policy and should be dealt with in accordance with HAZMAT procedures.
The trouble is that when the only tool in your box is a hammer then everything starts to look like a nail. Since you are familair with the topic you will understand the clear danger that will emerge if the high rate of CBRN false alarms continues and why people are getting concerned about that
I agree it is not easy. For example the full response to the small matter of a cook dry frying red chillis in central London last year was appropriate because a number of people did suffer a physical response that could have been indicative of some far worse.
But some tiny enclosed samples used as sources for school experiments found in a box with no indication of malicious use? Come on now, first responders have to use their smarts, call the risk as CBRN, HAZMAT or bugger all to worry about and initiate a scale of response accordingly.
The blunt All or Nothing approach is unsustainable