I talked about this when the current version was released with the personal warding item. I warned that Warding should top out at 90% from all sources to prevent creating units that are 100% resistant to ambush.
In a game with Tabalini, I noticed this problem with a Ranger. Her personal warding allowed her to reach 100% warding making ambush impossible. This is a problem because in this game (Snowflake map) there is a gob of items freely available as part of the 'item race'. What happened is the Ranger has a +1 hits item from this gob and combined with a horde of items she is about to become a 55/3 unit in a stack with 70% ambush, +20 chaos etc. There is no effective way to stop her from simply killing everything she encounters.
Warding for any unit should top out at 90% to prevent this.
KGB