It is important to note that this particular "y'all" is obviously fake and can be distinguished by such characteristics as a noticeable pause between the "y" and the "all" because the poser cannot even grasp the basic pronunciation of the word, and by their grammatically incorrect use of it to refer to only one person, when in fact y'all is one of the contracted forms of the second person plural "you all."
Poser: Hey Y'ALL, how are Y'ALL doing? Y'ALL, I was just calling to tell Y'ALL that I wanted Y'ALL to do me a favor. Could Y'ALL... (it can go on forever!)
Poser's Dad: What the hell? You're from New York. Stop y'alling, you poser! *Hangs up in frustration.*