If they use hot weapons, or especially penetrative weapons, or if they fire at dangerous things. Richochets are not a noted issue.
p8 of the Director's handbook notes this as an example.
To disarm an unexploded warhead
Other examples include this, from the Kafer Sourcebook p56.
Firing a Kafer weapon is
considered "Hazardous," requiring a ...
Per this thread the meaning of specific levels of symbols (and the other elements of the cultural extension) hasn't been given definitive meaning by Marc Miller.
However the developer of the Traveller Map has come up with this table. Which is consistent with how it is generated (d6-d6) + Tech Level. The higher the tech level is, the more abstract and ...