I always late register and have success in MTTs doing so.
If it's a RB/A, I register as late as possible, take the re-buy, then play uber tight until the add-on.
If it's just a re-entry, I late reg with ~20 BBs and don't re-enter after that.
I'm completely find starting with ~20 BBs and playing a super aggressive game to build a stack. Most players at the microstakes are really weak in the mid-late stages with average stacks and are easy to exploit. Yes, luck plays a huge factor when starting with such a low stack, but if I am able to take advantage and run well in key spots, I'm good.
The main reason for doing this is because my style is to play uber tight at the start and uber aggro at the later stages when a lot of players tighten up as they get close to the money. Since I'm not going to be playing many
hands early, instead of bleeding chips, I just late register and it's basically the same thing.