KK+? I would call that being too tight! AKo is very good in against SB's ATC and doubling up will greatly increase the ITM play. If folding both blinds, Hero is stuck with 1,5BB afterwards, and ÚTG will not bust nearly every time, and in the many cases he doesn't but doubles up instead you are left with absolutely no room to survive the bubble!
A little calc to back up my point:
Hero's ICM EQ(F) = 14,8%
Hero's ICM EQ(cW) = 24,9%
Hero's ICM EQ(cL) = 0
If hero's EQ on average will be higher when calling than folding it should be an +EV move in my book, meaning Hero will need to win in 59,4% of the cases
(14,8 < (x*24,9)+((1-x)*0) <=> 14,8 < 24,9x <=> x = 59,4%)
Meaning he could push as tight as ~15% and we would still be have the needed equity vs him.
This calculation does of course not consider the fact that UTG is likely to bust next hand, which is kind of hard to calculate, since we would have to include how often he would bust, how often he would double up ( and on this limit even how often he would fold the blinds) to our ICM EQ(F) and ICM EQ(cW)
If we knew UTG would bust 100% of the times in the next hand, or it had been a DoN on the bubble, sure easy fold. But here I would call anyday (or preferably push PF, not that it does any difference, but I just like to get it AI when I know I'm ahead 
I don't know how loose a call I would make here, but somewhat tight for the reasons stated by the first two posts, probably something like 77+, AJ+, KQ!