Mut'ah marriage was mentioned in Quran (4: 24) and many authentic Hadeeths in Sunni and Shia books of Hadeeth. It was practiced by the believers and was encouraged by the Prophet Muhammad (SAWA) and the Infallible Imams (AS). This fact is recorded in authentic Hadeethes in Sunni books as well as Shia books. This is enough evidence for those who want to follow the Prophet (SAWA).
Usually Mut'ah marriage is not done in public as there is no compulsory condition to announce it.
Sunni books mention breastfeeding the adult ( woman breastfeeding a man who is non Mahram to her to make him able to see her with out Hijab) and claim it allowed , but can they prove that it was done by Abu Bakr, Omar or Othman?