Validators report STAC as valid although it is not

[m-mohr]

The JSON Schemas are not very complete with regards to (mostly) assets, links and summaries, e.g. #1241. Many related requirements are not checked. The Validators that we have all report something similar to a boolean "valid" or "invalid" although they can't fully guarantee the actual file is valid. Thus, implementors claim their implementation is valid although it is not and blame us for that.

In JSON Schema draft-07 we can't easily validate assets anyway due to them being an object of objects. We'd need to update to the upcoming draft and then it's still a major effort to make the JSON Schemas more complete (and they will likely never be fully complete).

So I'm wondering whether we should update the validators to explain that?
So if the validation status is currently "valid", maybe it should just say something like "no obvious errors found (but that doesn't guarantee correctness)".

Thoughts?