Firstly: I noticed that the rules do not specify that the opposing captain needs to be notified as to the identity of the free-agent you want to use, just that you're using one. This is bad phrasing that I'm about to fix. The identity needs to be mentioned. I encourage the use of free-agents as a great way to get some characters involved who didn't land a team - but it isn't meant to allow for surprise lineups.
Second: Given that a team may only use a given free-agent once and a free-agent may only fight against each team once we should have a place to track them... So, find that list below. We don't typically see a lot of FA usage during the season, but just in case:
Royal Pain FA Usage:
- Kalamere Ar'Din - Week 5 v Dirty: Black
- Kruger Allen - Week 6 v Team Fist