Ok, I suppose I can't really argue the GERD thing if it's true that they spend a lot of time on their stomach, I wasn't aware of that. But I still think the odds of this are low enough that it's unnecessary to not buy the One-Size as a precaution... IF the baby turns out to have GERD and IF their ped. thinks it's appropriate to have them sleep on their tummy because of it (considering the increased risk of SIDS this is something I wouldn't do without some serious consideration) and IF the diapers fit in such a way that they do cause the body to lift enough to cause an issue (many times it just wouldn't, depending on the child, his size/shape and how the diaper is being fastened at the time) then one can simply put the One-Size aside for times when the child is asleep. Lots of 'ifs' in that statement. My opinion I suppose, for whatever it's worth...
As for the connection to SIDS, I would honestly like to see some research supporting the notion that clothing one or two sizes too big can contribute to SIDS. I really think people are talking without experience here, because if you knew the bulk of the One-Size you would know that it's not *that* big and does not cause you to need super humoungous clothing. As it's been pointed out, you often don't even need bigger clothing at all, just maybe to pick certain types or brands of clothing over others. In order for clothing to become a SIDS risk it would have to be so big that it could risk shifting during sleep and going over the nose/mouth. I've used the One-Size and I just can't see it being that bulky that you'd need clothing that big. This is where actual experience with the One-Size comes in handy, as opposed to people who've probably never even seen the diaper talking about it's possible 'risks'.
I'm sorry, I know I'm getting myself in trouble here and some will think I'm being 'disrespectful' and 'contradicting' but I think this is getting pretty serious and inflammatory. To suggest that a product may indirectly cause a baby to DIE is pretty darn serious and shouldn't be made without some serious information to back up such claims. Especially if you're going to make these claims on the website of the company that makes/sells this product! Sorry but this is the ultimate in disrespect for ME!
What a parent choses to use/buy is their own business and I've even always been a supporter of the x-small Sandy's (used them myself, loved them, recomend them frequently and would use them again in a heartbeat!). But to suggest that using the One-Size could indirectly lead to a child dying is just too much.