Yes, I know a person who was denied entry on student visa.
Raising 2 issues. First he was on the student visa so he shouldn't have had the 5 year multi entry visa. Not sure about this one what actually Is the issue.
Second he had some nude baby pictures of family was red flagged for child pornography.
Most of my family members have been decline first time US visa and have been granted a visa every other time although they have blood relatives living in the US being US nationals.
My brother in law and a few friends with decent travel history have been granted first time 5 year travel visas without family being in the US.
Attending marriages of friends, business visits, or group tours are relatively genuine reasons