And then let me add my own opinion on the matter:
I have confidence in my
poker game, and so I ALWAYS want to be in my seat from the very first hand of the tournament.
The early stages of a tournament are all about accumulating chips. Yes, Kenny Hallaert's paper does show correct math for late reg, and yes, I understand and agree with him that very long late-registration can be taken advantage of by good players who understand how to play shorter-stacked poker... but for me, I would much rather accumulate chips slowly but surely over those five hours of late registration... and when those good players do jump into the tournament right at the end of late reg, well at least I've got a pretty large chip stack advantage over them by that point. To me, this MORE THAN evens out the equation, even if I fully admit that my poker skills might not be quite as good as those good players who are late reg'ing.
So I am always in my seat at the start time, or else, if I'm not, then quite often I won't even bother to register for the tourney at all, I'll just wait til tomorrow, or next week, when I can play it from the very start. It just depends if I'm bored or not, if I have nothing else to do that day, then I'll register late, its not like I'm afraid to late reg, I just don't see it as a huge advantage to wait (for me, personally). Hope that helps. Good luck at the tables!