It doesn’t really circumvent seniority. You bid hard lines, your seniority holds whatever it gets.

The ILIW is a 24 hr period that opens up and is a mad dash to trade trips with whatever got dropped into open time via vacation drops/training/etc If there’s “coverage”, which there is for maybe 45 seconds, you can trade down a 4 day or two for a day trip, and then rebuild your line as you need. The floor is 60 hrs, so you can’t go below it. There’s a science to it. People have multiple windows opened and sync their computers with the company software so at 7:59:58 they know they can hit submit and be right on the 8:00:00 dot to get a trade in (that’s ORD at least). It’s legit over in 1-2 minutes.

The SLIW is whatever garbage 8 hr 4 days are left that aren’t even built into relief lines. At this point in the month, there’s zero shot of dropping anything.