21 Nov 2012
I'm not exactly how this works, but I know it does happen. Twice in my Yahoo league, which has standard waiver settings, someone has been able to hack the waiver process in order to jump place in line, without using their waiver priority.
The first time it happened was earlier in the year when I picked up Andrew Hawkins. I tried to add him into my list of waiver claims, around 1 AM on Wednesday morning (mountain time). Suddenly he was on my roster, as if I picked him up off of free agency! Waivers hadn't been processed yet, and I didn't burn my waiver priority in the process. I notified the league commissioner and it was dismissed as something he couldn't do anything about, and likely a one-off event. No one else claimed Hawkins so it wasn't a big deal.
This morning I log on to see if I had set my claim for Ronnie Hillman, and I've noticed someone else did the same thing I did earlier in the year. But this time they've claimed three players - Blackmon, Arizona DEF, and Kaepernick. There are more players involved, and Kaepernick is potentially a huge pickup. And he did it at 1:19, 1:22, and 1:23 this morning. Again, it didn't burn his waiver priority. In fact, his priority is 9th out of 10, so it's unlikely he would have been awarded all of these players if the waiver process played out normally.
Here's a link to a screenshot to give you a better idea of what's going on.
For what it's worth, the window to exploit this has since passed. (Or some other key variable is missing for me) If I try to add a player right now, before the waivers have processed, it won't let me add anyone to my waiver list, nor will it allow me to pick anyone up. The + sign for adding players is greyed out.