Good evening John and welcome to the Events Calendar Support forum!
Thank you for reaching out to us.
I would love to help you with this topic.
On one of the events, a person has to check a box that indicates they are qualified to attend an Event.
What you suggested could work. But another idea would be to use the additional attendee information for that purpose.
In other words, you could have a Mandatory checkbox tied to the purchase process (along with the desired text.
Let me know if that helps.
Have a great day!
Geoff B.