This means while activly using a skill for you Rogues. If you get hurt disarming a trap yes the Gild will heal your damage.
If you get hurt fighting a monster on a module that you disarmed a trap on no healing for the monster damage. The Guild will only heal the damage done by a trap you tried to disarm, not all the damage you take on a module or running around "being a Theif". This same sort of thing will apply to Merchants. If someone comes into your shop and attacks you yes we will heal you. If you are roaming outside of town or hanging out in the Tavern no we wont.
Good standing means you pay your dues. On time, before you get hurt.