[wing-_-nuts]

Just because you can hit a backend without a rate limit, doesn't mean you should. In my experience, government IT is very humorless about this sort of thing. Far better to blend in with normal traffic than to stand out as a bad actor.

[Scaevolus]

Especially given how the response time doesn't matter much here! If you're just looking at 2-character license plates, that's 676/5=136 requests to check them all, and you could easily space that out to something like one request per minute to scan the space every two hours.

[ycombinatrix]

"Your honor, the defendant took steps to hide their activities, showing that they knew it was wrong"

[hun3]

Just append

  X-Crawl-Reason: Finding spare license plates, throttled ONLY to prevent service disruption. To the best of my knowledge, [legalese claiming good faith and compliance to all applicable laws]

(Mandatory disclaimer: IANAL, ignorance is no excuse for breaking laws)