Well, yes, but that's true clan or no clan, and the Titans can then easily find proof and lightning bolt the culprit.
If it is done IG, and if someone reports it, then yes, the Titans can find it. If no one reports it, then it will never be found. So far as I know, the Titans do not engage in fishing expeditions for IR violations.
Or do you think there are extra rules that they should submit to?
Everyone is subject to the same, simple rules. No exceptions.