Can I show my opinion in negative interrogative?

I believe

It is not safe to let strangers in.

How do I ask people and find out if they have the same opinion as me?

1. Is it safe to let strangers in?: It feels like to me that I have no opinion.
2. Isn’t it safe to let strangers in?: It feels like to me that I believe it is safe to let strangers in.
3. Is it not safe to let strangers in?: Many resources [1][2][3] claim this form is merely a formal form of option 2.

Someone told me to say

Is it unsafe to let strangers in?

How about this one? Is "unsafe" equal to "not safe"? Can you rephrase the question using "not"?

1. https://www.englishgrammar.org/negative-questions/
2. Why do not we ask negative questions without a contraction on the not after the verb?
3. "Do you not" vs. "Don't you"