I've read that parts of the game, you go suitless, apparently taking more damage (imangine that) and maybe losing abilities. No exact clue why yet, but as far as i know its not like the justin bailey code where you go the entire game like that.
On another topic, i don't think theres a huge amount to spoil in the metroid series... they don't have hugely deep storylines, at least not in the way of character interaction. and its a given that samus doesn't die, she eventually kills the big bad evil guy(s)... and gets new items along the way... basic premise for everygame. oh, and ridley is always defeated, and in the 3 i've played you always get a unique beam useable only for the last 5 minutes or so of the game.
Up until Super, you would have been 100% correct, but Prime and Fusion seem to start a move to involve more complex plots, actually telling a story instead of just "Samus goes to planet, kills stuff and blows the planet up". Losing the power suit for plot related reasons is arguably a spoiler, but if I accidentally find out how and why before I play the game because someone didn't mark a topic spoilers...
Yeah, this isn't a major major spoiler or anything, but thinking along the lines of someone who was trying to avoid ZM spoilers as much as possible, I'd be irked to find out that Samus goes suitless in any context whatsoever from someone who failed to mark for spoilers. I myself am not really going out of my way to avoid ZM plot spoilers, but you have to remember that some people are.
Considering Prime and Fusion were too old for spoilers when most of us got here, I'd say one or two slips are to be expected now we finally have stuff to stick spoiler warnings on.
RoboBlod, I'd suggest you take that signature image off, or at least reduce its size to a decent and tolerable one (stretches even MY screen, at 1024x768 resolution).
As for Suitless Samus, if anyone's interested in knowing what happens, PM me. Indeed, the power suit is lost due to plot development reasons.