Did you mean no documented procedures?
Or no procedures documented to the extent necessary for effective control?
I don't want to misrepresent what Bev is describing, but it appears like we are talking about "an absolute minimum amount of method and process documentation", which is laudable.
Hypothetically, you could envision a company with no process documentation at all, but whose records/data indicate everything is functioning perfectly. How many auditors would be ok with this? Notwithstanding any requirements within the audit scope that explicitly call for procedures, auditors should technically be fine with this, assuming interviews with personnel indicate that appropriate control is maintained.
However, in my experience, how auditors react to novelty is uncertain and increases chances of increased scrutiny and having to contest (perceived) non-conformances. Uncertainty is undesirable for our business, and there is certainly a risk-assessment of the potential regulatory & certification headaches of adopting novel, undocumented approaches that weighs in favour of the documented approach.
As an aside, the same goes for recognized/harmonized/concensus testing standards. Technically you are free to go "off script" and develop your own tests - but if your business depends on the outcome of an FDA review, it can be a huge risk to deviate from status quo (unfortunately).