Disable a Device is a trained action for the Thievery skill, so only those trained in Thievery can do it. However, some hazards say "Disable DC ?? Thievery (trained) on...", and others just say "Disable DC ?? Thievery on...", suggesting that being trained in Thievery isn't required by default. What's going on here?
There are also some hazards that list Disable: DC xx Thievery (expert). So if the hazard doesn't list a proficiency needed for disabling it, then you need to be at least trained because that is the minimum for using the action. If the hazard lists a proficiency, then you need to have that level of proficiency in order to succeed at disabling it. Otherwise you will get a failure result at best.
There are also hazards (especially Haunts) that list different skills, such as Disable: DC xx Diplomacy (master) or DC xx Religion (trained).
Yes, I'm aware that sometimes a hazard will require the Disabler to be better than trained in Thievery. What confuses me is that some don't list a proficiency requirement and some say you must be trained, even though you need to be trained to Disable a Device at all.
It might be because of the human ancestry feat Clever improvisor.
It lets you use skill abilities you are not trained even though it doesn't actually make you trained in them.
Edit: Baaroque got to it first.
There might be enough wiggle room for a really good rules lawyer to get a loophole that a hazard that doesn't list a proficiency and uses a skill other than Thievery could be successfully disabled while untrained.
The Disable a Device action is for the Thievery skill alone and it lists a minimum proficiency of Trained in order to use the action. The rules for disabling a hazard with a different skill only copies over the action cost and traits of the Disable a Device action - not its proficiency requirement.
But I don't expect that to be an argument that many GMs are going to allow.
There are feats that allow you to perform "trained" actions despite not being trained. Perhaps those hazards have the (trained) note as an extra layer of specific gatekeeping to prevent those with such feats from being allowed to disable them
Good catch.
More likely I think it is just a difference in author style.
I also note that the two hazards I linked to earlier don't actually have the same format for their Disable entry.
The Hammer of Forbiddance lists Disable: Thievery DC 28 (expert)
While the Blood Tears lists Disable: DC 30 Diplomacy (master) or DC 32 Religion (trained).
Note the different order of wording. The Hammer of Forbiddance lists the skill first and then the DC. Blood Tears lists the DC first and then the skill.
I don't think that difference is actually relevant - just a difference in author style.
So I can also believe that the difference between 'Disable: Thievery DC xx' and 'Disable: Thievery DC xx (trained)' is also just a difference in author style. Not a mechanical difference in the proficiency needed for disabling the hazard.
There might be enough wiggle room for a really good rules lawyer to get a loophole that a hazard that doesn't list a proficiency and uses a skill other than Thievery could be successfully disabled while untrained.
The Disable a Device action is for the Thievery skill alone and it lists a minimum proficiency of Trained in order to use the action. The rules for disabling a hazard with a different skill only copies over the action cost and traits of the Disable a Device action - not its proficiency requirement.
But I don't expect that to be an argument that many GMs are going to allow.
I'd allow it, since it is in fact not Disable a Device. Besides that, I believe the intent of allowing different skills is to let more players have an opportunity to disable the hazard, so it would make sense for untrained Arcana to be allowed if there is no proficiency requirement. I don't expect it to come up too often anyway, as an untrained creature has so little chance of disabling the hazard that they should probably use those 2 actions for something else.