description

Confusing Necessary with Sufficient Conditions is pretty common. Generally, it's a misinterpretation of an implied 'at least', or 'to be considered'.

examples

"You need a 2.5 GPA to get into UBC Medicine. Therefore all C+ applicants will get in."

"You need to be 19 to get into the pub. You're 20, so you can't come in."