Ann: STX:Strike Off Market Takeover Bid for Warrego - Offer Opens, page-5

It's probably just the date that STX obtained the register for the mailout. Above my paygrade but I think the concept of restricting acceptance would need to be spelled out a little more clearly than that, there could easily be people buying WGO today in anticipation of accepting STX. Doesn't impact me but if anyone is concerned they should pick up the phone and call the hotline for confirmation.