When is lens flare acceptable?

Are there any skilled artists or photoshoppy types out there that can give me an insight on whether or not lens flare is an acceptable thing? From what I understand, lens flare is something of a godwin's law in digital art circles: use it and your credibility is shot.

But is there any leeway?

Take these two images. The first is 'Doctor - the Cyclops Scientist'.

In the future, all science will be done in the dark and look ten times cooler.

And here it is with lens flare added. Is it okay, given the context of a reading light strapped to the man's head?

In the future, all science will be done in the dark with SWEET LENS FLARE and look FIFTY times cooler.

Does it really matter?

At midnight on a Tuesday, probably not, I suppose.