A couple reactions. My first is that getting youth involved with the platform is wonderful. As with any youth onboarding there will be a need to reach out and explain to them how the platform is used. As an instructor since 1984 I am keenly aware that few students will light up to a particular subject, but those few will go on to make great contributions to the field.
My second is based on the three students at the links having joined on the same day as the field trip suggests that like me, the teacher may have not known how the iNaturalist community functions. Downloading iNaturalist is as simple as downloading FaceBook or Instagram. Many platforms now have some form of brief on onboarding tutorial. When I downloaded iNaturalist 30 minutes before my class and then had students using the app during class, I had no idea there was a community “behind” the app nor that the data would be flowing into biodiversity databases. The need to onboard users is discussed elsewhere, as is the need to steer teachers during the onboarding to appropriate materials and to not generate “duress” users.