‘Double-blind’ trials that do not include a test of the ‘double-blind’ design are inadvertent social information about those who design, approve, perform and publish the trials.
The failure to test a supposedly ‘double-blind’ design increases the likelihood of a false positive result, and thus the likelihood that you will be given a treatment that has toxic side-effects but no therapeutic effects. You would think that the Health Research Authority and the General Medical Council would want to distance themselves from this consequence, by asserting formally the need for a test of a supposedly ‘double-blind’ design as a condition of ethical approval of a research project. Perhaps the issues are too complex.

Would you accept a supposedly innovative drug if you found out that the research which had identified the drug had been biased in favour of the researcher breaking new ground; that this bias would increase the likelihood of you, the patient, being given a drug that would be at best ineffective and at worst harmful; and that your prescriber knew all of this?

A false positive result makes the researcher appear to have made a new discovery, while the patient is given a treatment that is ineffective at best. Why does the medical profession not try to avoid a false positive result by testing to see if the researcher actually knew which patient was receiving which treatment, and was therefore able to bias the results in favour of self-advancement at the expense of the patient? So much for the peer review system: herd impunity, with an evolutionarily stable strategy driven by personal aggrandizement and financial gain.
When a reference was made to the failure to test for successful masking in Wikipedia, it was removed within a week.

Prior authorisation waiting to happen.

Humans are not alone in turning their backs to achieve false positive results. Grey squirrels with nuts turn their backs on watching grey squirrels while digging, so that the watchers do not know if the nuts are actually being buried, or if they are just being kept in the mouth, to be enjoyed shortly, after leaping off.

In a ‘single-deaf’ trial, experimenters did not test their belief that they could not hear the stimuli presented. See also Punctuation and Verb number.