You don't get banned based on Skype. Those who lost acres to skype lost it due to violating their terms of agreement elsewhere (upload studio)
Of the few (12?) some received a 24 hour ban from the app.
A Microsoft representative responded to our requests, explaining that the company does not monitor private Skype conversations — however, "excessive profanity" in Upload Studio videos will result in suspensions.
"To be clear, the Xbox Live Policy & Enforcement team does not monitor direct peer-to-peer communications like Skype chats and calls," the representative wrote. "Also, we take Code of Conduct moderation via Upload Studio very seriously. We want a clean, safe and fun environment for all users. Excessive profanity as well as other Code of Conduct violations will be enforced upon and result in suspension of some or all privileges on Xbox Live. We remain committed to preserving and promoting a safe, secure and enjoyable experience for all of our Xbox Live members."
It would seem the users who posted screenshots of their Skype application preventing them access received a full Xbox Live ban in another app