Inspection sticker, smack dab on front of trl. The hostler is the first person who can catch an empty trailer with an expired sticker, run it by the shop, verify it is really past due. If it’s due, now red tag it, before it gets loaded. So many times, I find my trailers with expired sticker, so first thing I do, I have shop check, to see what’s up, and after researching find the proof that the inspection was done, just missing new sticker. If inspection is truly passed due, trailer needs to be red tagged, loaded or not. Don’t be intimidated into leaving the yard with a trailer needing it’s inspection, period!