There are good arguments for playing either loose or tight at the early stages of MTTs.
I, personally, prefer to play a little tighter that the start and get looser as blinds increase. The main reason for being is that I know a lot of players play really loose at the early stages and by being very selective, I can easily get paid off on a lot of big hands.
Another reason for choosing to play tight is because most MTTs online have very fast blinds. The standard 10-12 minute blinds isn't that long at all. And, depending on how fast the table is moving, that might only be 6-8 hands per blind. How deep starting stacks are also play a factor but, for the most part, I'm looking to really conserve my stack as much as I can for the later stages where I can open up a little wider and play a bit more aggressively.
Also, a lot of bad players tend to tighten up significantly as blinds increase and I can take advantage of that with a much wider range more than I could in the early stages. Especially as it gets closer to the bubble.