[seafoamteal]

It's weird that none of the systems automatically fell back to disambiguating with a number or something similar if the 'proper' one already existed. I'm wondering if you were a year or two apart instead, would the system simply silently fail to create a new username for the younger sibling when they joined?

[philipwhiuk]

If they were a year or two apart the DOB would have disambiguated it.