What does this sentence mean?

Where did you find such a sentence?

at a USMLE forum

blues, Shout "Houston, we've got a problem."

BTW, Welcome to a2k.

It means that the warning to stay away is unnecessary, because most people are smart enough to stay away even without the warning.

Fragment, I say! LOL

The writer appears to be calling attention to their opinion that someone's action in warning others away is superfluous, since most people are clever enough to stay away anyway.

Does this sentence mean "only a handful of people are to stay away"?

Thank you so much. I think I got it.

We aim to please!

And welcome.

Brandon said it succincter than I did.

"how you're warning people to stay away when only a handful of people are dumb enough not to"

Brandon may have given the most likely interpretation, but the sentence does not really mean anything because it's not well formed.

This is not a valid sentence because "how" must be followed by a form of to-be...it's obvious that the writer MEANT "how are you..." instead of "how you're" which is a contraction for "how you are."

At that point, it looks as though it's more likely that the writer meant "why" instead of "how" because the second part of the sentence.

"Why are you warning people to stay away when only a few people are dumb enough not to stay away"

Once these replacements have been made it's obvious that the sentence still doesn't make any sense, because the first part of the sentence implies that people should leave while the second part implies that they would be dumb to leave.

Most likely the writer confused himself with the negatives, and finally meant what Brandon said...

Now that you have made the writer's intentions clear, it seems to me that he is rather cold hearted, since he is willing by eliminating the sign to let the few "dumb" people submit themselves to danger.