Yes & No yes the ignition switch isolates the air bag control modules, however the propellant charge is still "live" as is the seat belt pretensioners etc.
Therefore a stray spark may set it off & I did say may!
The current thinking is Keep out off it's deployment path! You are correct - the use of restraint systems for airbags is no longer practiced.
Also madly rushing in & disconnecting batteries is also not encouraged, as modern seat adjustments, windows etc all need electricity to work & if you disconnect the battery you loose that option (reconnection is not encouraged!).
Going forward the modern cars are moving batteries to the rear of the vehicle & it is likely the days of the old 12 volt battery are numbered, due to the increasing technology requiring more power.
The main point is Keep out of the deployment path! Simple.
There is a lot of urban myths about the whole subject, that is why up to date training is a must.
Anyway I hope that helps, I'm sure the more knowledgable of us can add more
cheers