I had an issue with LOT on Sunday where the BP on my phone initially would't scan at T1 - I was headed to the Polaris lounge. It was odd- ORD- WAW wouldn't scan but WAW-DUS would. The kind TSA agents told be to go back out to print my BP, but, um, LOT has no presence in T1. So I instead took the landside shuttle to T1 - hot as blazes, flies - hundreds of flies, and the trip from T1 to T5 took 30 minutes, but that's all another story.

In any case, I got to T5 to find that the LOT desks didn't open for over and hour (I was planning on Polaris time). Having time on my hands, I discovered that I had an email BP with a PDF as well. When I opened that it gave me a different BP barcode. Not sure If I was supposed to use the fast lane for my LOT Business class BP, I spotted the fast line all the way to the left and thought "let's give this a try", there was no line, the agent waved me through and the BP scanned just fine. No line and very easy.