Absolutely.
Being at the wrong place at the wrong time does not constitute reasonable suspicion much less probable cause.
Second question to think about: If the answer to the first question was "yes", what would have been reasonable?
A warrant based on probable cause.
“A warrant based on probable cause.”
And “particularly describing the place to be searched,” when that involved “miles of cars”, probably hundreds?
How long would it take to get such a warrant? Should the vehicles and people be detained for however long it takes? Would the fleeing criminals have more time to find a way to sneak away?