Sources connected to their Cannes crew tell us Bella decided to back off the festivities, and away from Scott ... after witnessing how wild he got. We're told the heavy drinking was especially shocking to the 19-year-old.
When 34-year-old Scott invited Bella to Cannes ... we're told she insisted her older sister, Dani, come along too. But even with a chaperone, and several other friends, Bella reached her limit. She hinted at her frustration Thursday on Twitter.
Sources close to Bella's fam tell us her parents were worried anyway due to Scott's reputation and his age -- but they stayed out of it because she's an adult.