To put it super simply to you 2 (and others).
If you're running a meeting tomorrow, and you notice an employee texting, are you 100% confronting them, in the middle of the meeting?
if so
Are you going to keep belaboring the point if the employee continues to text?
If so
Are you going to fire the employee?
if so
Are you going to call the police to have the employee removed if they continue to sit there?
OR
Do you think somewhere along the line, you realize that you're not having a productive interaction, and decide to continue your meeting, and then apply the appropriate punishment the next day?
Because anyone with a brain cuts the interaction short before firing the employee (during the meeting) and confronts the employee after the meeting.
And if you did that, and say fired the employee or demoted them or docked their pay or whatever punishment you decided was appropriate, do you REALLY think everyone is showing up at your next meeting and texting?
If someone acted like she did at a business meeting at my company, the owner would have told her to leave. If she refused to leave, he would have called the cops. The cops would have removed this individual. The exact same thing would have happened, expect no one at one of our meetings would ever act like that.