Suppose as a coach you have a student that has wildly improbable dreams of playing tennis professionally based on what you know as a coach. Should you be honest in your view and dash their dreams or allow those dreams to go forward. This is especially important to consider when a student plans to skip college first and try to play professionally. We all know that unless they have a high national ranking in their own country that it is unlikely that they'll get very far.
As an example, I taught tennis to beginner and advanced beginner students in college classes where one now and then actually thought they could someday get out there and be on TV playing tennis for a living. Rather than bother with deep discussions on this I'd always just suggest that we get them past the other players in the class first.
So then you have students that have their parents believing in their dream as well. Again, do you attempt to dash the dream usually at your own personal expense since they'll likely move on or quit rather than stay with you. Or, do you just help them keep moving one step forward toward that unlikely goal regardless.
Here is the thing. It is very possible that this student that must love the game will do anything to stay with the sport even if it is somewhere else in the tennis industry. If they skip college early and go toward a competitive career it may end up being a dead-end for competition for them but it can lead to contacts in the tennis industry. I know a number of examples of this including friends that became professional stringers for the tennis tours and others that became reps or fellow coaches. All is not lost and reality will let them know that the other options may be their only remaining options if results don't match expectations.