Add a new Artifact trait of “Locked” to the table in “Valuables”, with this effect:

Can’t be taken in the first two Minutes of a Break-In, or by Burglars who weren’t present in this Artifact’s Location during both of the previous two Minutes.

In the Effect of “Keycard”, replace “The Alarmed effects of other Artifacts do not apply” with:-

The Alarmed and Locked effects of other Artifacts do not apply

Replace the Effect of “Disguised” with:-

Can’t be taken by Burglars who are not Observant.

Add to the end of that rule:-

If an Artifact “can’t be taken” in a certain circumstance, this means that if an Agent would start to hold it in that situation, the Artifact instead does not have its Location changed.