The owner of the survey form is the Old School RuneScape team. That line on the survey form is a generic warning from Microsoft (whose service is being used to host the survey) not to provide sensitive information over a form, and is likely posted on the bottom of any form published using their service rather than being unique to this one.
There is no personally identifying information collected on that survey, it is all multiple choice answers. If the survey wasn't safe (and wasn't being run by the Old School team) it wouldn't have been the focal point and linked within the devblog.
As such, there is no need to question the legitimacy of the survey any further than this thread has.
11-Oct-2023 04:46:00