I would like to point out that the thing with gift pack is that they give full ninja value of frags. Which means on "repeats" it is far more valuable than getting a repeat of a ninja, which is 1/4 the value.

So while in the short term this is a reasonable replacement for a kage drop (replace every 3rd kage drop that is), in the long run, this is actually 4 times better.

Given that, this is ever more unlikely than you might first think, as in the long run it basically doubles your kage frag income (80+20+20=120 per 180 pull instead of 20*3=60)