Samsung isn't just relying on warning labels and "read the manual" suggestions to prevent people from inserting the Galaxy Note 5's S Pen the wrong way. A Phandroid reader has discovered that newer Note 5 models have an updated slot design that makes it feasible to eject a backwards stylus without breaking the detection mechanism -- you won't have to panic because of a simple mistake. It's not certain which models have this stealthy upgrade, although it wouldn't be surprising if many of the freshest units make the grade.
Samsung hasn't commented on the change. It's not a shocking move, however. Many companies make quiet revisions to devices in response to flaws they didn't anticipate in the design process. It's just that this flaw happened to be made very public very quickly, and was relatively avoidable (earlier Notes didn't have this issue). One thing's for sure: the chances of wrecking your giant new Samsung phone should be that much lower.