[frog in a pot]

There goes any probable cause right out the window.

Wouldn't that depend on the feedback?
A clean report would mean the LEO is left only with whatever he observed, which in the event of a random stop is nothing.
Of course, if something improper comes back it is no longer a random search.

You may mean that the "lookup" itself, similar to an ordinary investigation, is conducted without probable cause and you certainly would be correct. Going one very small step forward, it seems possible that in the near future the response to the "automatic" lookup could include all manner of problems such as failure to file state or fed taxes, over due library books, etc.

[Ray76]

>> You may mean that the “lookup” itself, similar to an ordinary investigation, is conducted without probable cause

Yes exactly.

Some Florida municipalities scan every vehicle entering and leaving. Manalapan comes to mind. They began scanning around 2005 or so.