What a great way to ruin a perfectly awesome company.
I personally know at least one company that has been profitable from the very beginning and took 3 rounds of VC already, always on the same terms: "we don't need your money, so we'll sell you a very small piece for a large sum and run with it the way we do today". In the end, it's a great way to either cash-out, put some money in the bank to avoid future surprises or launch new experiments/products with minimal risk...
is it possible the maximal risk they encountered when building github with their own cash helped make the great product github is today? history has shown time and time again if you give someone a long enough rope they will hang themselves, doesn't mean that's githubs fate of course, but they're certainly opening a door of influence that wasn't around through the initial building of a great product.
If you give someone a short enough rope, they'll never be able to get out of the hole...