Just another parent perspective – I think there is a difference between programs which (1) cost money which are part of a student’s overall commitments/interests/trajectory and (2) cost money and are more like “add-ons,” generic enrichment etc. A dedicated dancer, fencer, etc. will have invested years of time and money in reaching their level of expertise, and will likely have spent time in summer intensives, competitive camps/programs. It is reasonable to include that on the application as it shows the depth of a student’s commitment etc. That is different from the kid who does a $7000 summer program at an Ivy League school AND puts it on their Common App list of activities. To me, that summer course could be well worth it, from the family’s perspective, in terms of helping the student develop autonomy, become more comfortable with living with new people etc. If the family can afford it, and wants the student to have the experience --great. But it would not be worth taking up a spot on the Common App for it as an activity as it does not really demonstrate “who” the kid is. Of course, it could be more nuanced, maybe a kid is intellectually engaged with international affairs, speaks multiple languages, and does a summer high school program introducing them to foreign affairs in D.C. – that could be part of the kid’s story, even though it is “pay to play.”
At the end of the day, consider what a particular activity communicates to the college about the applicant – is it part of a coherent story or a random add-on.