That was a hypothetical example. I suggest you peruse the 654 pages of this thread to find all the spoilers and then determine if each one could have simply been avoided by controlling your eyes. Many of them cannot. In fact, the one referenced on this page or the last, which has since been deleted, involved nothing more than bolding a phrase in non-spoiler post to reveal something that purportedly happens in the comics. I think I have pretty talented eyes, but I don't think I can train them to avoid boldface type.
How about this instead. If you're going to post a spoiler, instead of relying on the level of control every reader has over their eyes, how about you simply put the content in spoiler tags? After all, that is precisely what spoiler tags are for. It's simple courtesy really.