I imagine that the logical thing is that the flag is created by someone directly affected, but if it is created by a DT not directly affected, would it contravene any rule? I don't think so.
Well, in flags Type 2 and 3 it is explicitely stated
"This user violated a casual or implied agreement with me/This user violated a written contract with me" so its not correct to create one if you are not affected by it and flag Type 1 should be used in that case.