Actually, the use/misuse of terms like y’all, all y’all, alla y’all, or the highly advanced plural possessive “y’all’s” (sometimes pronounced “y’all-zis”) are excellent red flags to know whether or not you are dealing with a bulls****er. If they use a glottal stop when attempting y’all (yuh-all) then it’s a big red flag.
The more important question is if they say “reckon,” “fixin’ to,” and “warter.”
That complicates a simple thing. I say, many say, stuff like All y’all for emphasis or for being funny. Nothing more. The way you pronounce it can be a trigger. Texans unite! Dallas and all points around the Lone Star State!