Yes Master. . . .

I've already compromised myself--I'll never get those photo-ops with Brian Cox!
Master, we already went over this, when you said you weren't too concerned about a black hole eating up the Earth within 300,000 years because you figured a GRB would do us in within 100,000 years. That's why you're confusing me. You're forgetting what you've already admitted.

Well, I went back over G&M's formulas to do a worst case scenario for a 6-D mBH in the macroscopic regime. G&M's formulas (4.46) and (4.49) (p. 25) have a parameter λ_D that can range from 3 to 6.6 for D > 4 and from 4 to 18 for D = 4. Thus the higher the λ, the shorter the accretion timescale. G&M just set λ = 4 for their numerical examples, a conservative, but non-worst case assumption. A truly worst case assumption would use the highest allowable λ. Thus according to my calculations (for D = 6):

(4.46) (λ = 6.6) t = 8,333 years (6-D subatomic to atomic transition)
(4.49) (λ = 6.6) t = 14,697 years (6-D atomic to 4-D transition)
(4.49) (λ = 18) t = 5,388 years (4-D to M_Earth transition)
total t = 28,418 years

(You have to do equation (4.49) twice because it covers two phases of evolution: (1) growth from atomic scales to the point where regular 4 dimensional growth takes over; and (2) the 4 dimensional evolutionary phase where the black hole grows until its mass = M_Earth.)

So, under a worst case scenario for a 6-D black hole, the situation could get potentially problematic an order of magnitude sooner than the earliest "conservative" estimate of time until potential problematicity that I could glean from G&M of ~ 300,000 years.

Therefore, Hawking radiation is more than just a bonus for theoretically harmless mBH's that can't grow fast enough to be a potential danger. There are allowable choices of parameters that do allow for potentially fast growing mBH's. It would be nice if Hawking radiation could provide an absolute safety guarantee, but unfortunately, Hawking radiation cannot provide an absolute guarantee, and if Plaga is correct, Hawking radiation can be a danger in itself.

Then there's the astrophysical arguments. Unfortunately, they cannot provide an absolute safety guarantee either. So all we have are a series of arguments that say that the LHC is probably safe--but this is a far cry from having a reasonable certainty that the LHC is totally harmless, at least on global scales (it seems like a dangerous place to work with all the mishaps going on). And when the Home Planet is on the line, we must insist on reasonable certainty as the only allowable standard of proof.