Are men who just cold approach us on the street to get to know us and ask us out LVM?

I haven’t met any men at work, nor through my one friend I have or anything so I was wondering if men who cold approach me on the street to ask me on a date is a red flag?

If so, why? I have never said yes to a man who cold approaches me but that’s the only men I’ve even met so they’re the ones who ask me out. Is it a terrible idea to say yes and if so why?