I'll add one more thing...
Some may say, "Why not respond to every camp / showcase invite? You never know where it may lead..."
Any communication could lead somewhere. Anything's possible...I will agree with that.
Getting an unsolicited email from a school the player/family don't know about can definitely prompt research to see if the school is a good fit academically and athletically. If it is, then maybe it belongs on the player's vetted list of schools.
But I'm not sure responding to every email because the player's name made it to a mailing list makes much sense.
IMHO, if homework is done upfront and a vetted list of colleges is prepared (and evolves over time), then the player and family can be focused in their search for the best fit. Once a player is focused on communicating to the schools on their vetted list, then there is a lot of things to communicate to/with coaches and with Admissions reps. And doing so regularly to both demonstrates interest by the student athlete.
My boys received hundreds of unsolicited camp and showcase emails (my 2016 received two today!). Responding to all of them ultimately becomes a significant distraction from the player's vetted list of schools.