Not really if the non-time-out wrestler has momentum going his way, then he is put at a great disadvantage when the other STOPS that momentum to use an injury time-out. But, they are in the rulebook so he can 'fairly' do it. Obviously it is unethical if he isn't really hurt but that is just another can of worms.

Related: Somebody was putting a whipping on Ali once (I think it was when Cooper knocked Ali down at the end of a round - Ali was pretty much 'saved' by the bell'). During his time in the corner - Ali's trainer pulled the stitching out of Ali's glove. Then runs to the ref and says, "look! Look!" It takes another 2 minutes to get Ali ANOTHER set of gloves. Many, many years later - Dundee admitted to doing this to give his man more time to recover. Which he did and he came back and won the fight with a KO.