[RTTY] Question about Super Check Partial files

[Bill, W6WRT]

I am curious about something. As RTTY contesters probably know, WA1Z has
recently taken over the creation of the Super Check Partial files from AA5AU. 

On his (WA1Z) website appears the following:

"All files submitted become the property of WA1Z and will be used only for the
purpose of creating the master call files."

I find this strange. What is the reason for my log becoming his property? Surely
there must BE a reason or he would not have bothered to post the notice.

I contacted him when I first saw this but never received an explanation, only a
reiteration of the statement.

Does anyone know? 

73, Bill W6WRT