It feels forced. That's the crux of the issue. If adults don't verify, they risk being locked out of instances, unable to join friends or participate in events. They may also be restricted from using their NSFW avatars, even when alone in a private instance with their adult partner. When something is "forced" to the point of exclusion, there should be a more accessible verification method that doesn't involve surrendering an ID and a selfie. I'm unconcerned if a few kids manage to circumvent a simpler verification process; after all, VRChat is a game, not a financial institution or a real-life club.
Personally, I would approach it differently. I would award all current VRC+ subscribers a new badge, labeled not as an "age badge" but as a "Verified User" badge. If users desire more controlled environments, they could create "verified only" instances, which would be exclusive to VRC+ supporters. This way, any adult could easily get "verified" by purchasing a VRC+ subscription with their card, avoiding the submission of sensitive ID documents, and adding a layer of verification while also supporting VRChat. This seems like a preferable alternative to submitting personal identification. To obtain the verified badge, an active subscription is required; merely receiving a gifted VRC+ would be insufficient.