If everyone’s using it, then it’s still beneficial in obscuring your actual data. Even better since they can’t just discard the date outright as it is a viable birthdate.
Realistically it won’t be that many people in their networks of data that use the same date, 01-01-1970 in this case, and they might even use that trend of date when possible to infer that you like technology or are in certain circles.
Random dates sound safer to me. I don’t see how using random ones could end up in some unique-to-you pattern.
Setting a different date every time sets a (probably unique) pattern. Everyone using the same date every time makes it useless.
But what if I was born on New Year’s Day in 1970?
If everyone’s using it, then it’s still beneficial in obscuring your actual data. Even better since they can’t just discard the date outright as it is a viable birthdate.
Realistically it won’t be that many people in their networks of data that use the same date, 01-01-1970 in this case, and they might even use that trend of date when possible to infer that you like technology or are in certain circles.
Random dates sound safer to me. I don’t see how using random ones could end up in some unique-to-you pattern.
Xkcd illustrates the issue nicely: https://xkcd.com/1105/