
An enemy signature weakness, designed to annoy Trish. Looking at the two elements, the effect and the discard condition, we get:
The effect: There are three ways to deal with this weakness, the mug's way, Trish's way, and Trish's other way. The mug's way is to fight them; that is likely to be 2, maybe 3 actions, although another investigator can always do the fighting for Trish. Trish's way is to evade them. As a , Trish has a lot of evade options. The entries above give some good suggestions, and Slip Away, Slip Away (2), Stealth, and Manual Dexterity (2) can help with the test. Trish's other way mostly involves boosting investigation checks and using Obfuscation to ignore the AoO (or just eat the damage; Trish has 8 health) and relying on Trish's special ability to evade them. The real secret of the Shadow Agents is: why are they hunters? If they get discarded, they aren't going to hunt, and there aren't too many cards that move an investigator without bringing the enemy with them.
The discard condition: Evade them or kill them.
All in all, this is a below average signature weakness, like most enemy weaknesses.