1) She could’ve just left it sitting on a table with friends.
2) Young people don’t turn away from microphones and cameras
Look at things like rolling a set of dice.
What are the odds that someone would leave their phone unattended. What are the odds that someone would entertain a stranger who put a camera in their face and asked them to take part in a transparency game.
What are the odds that someone would do all of the above when they know they're sleeping around.
Then you can throw in other points like what are the odds that they would all have names starting with J. What are the odds that their reaction would be enough for entertainment but not enough to alert people who are not in on the skit.
Once you start looking at things mathematically it becomes harder for people to pull the wool over your eyes.