The current rules already address what this proposed change is trying to achieve.

A player who hits a ball that goes out on the opponents’ end of the court may call their ball out, per Rule 6.C.11., which states “Players may overrule a partner’s line call, their own line call, an officiating team’s line call, or an “in” ruling to their own disadvantage.” When an opposing team does not call a ball out, by rule it is “in”. Hence, it’s an “in” ruling, which may be overruled by the player who hit the ball out.

Furthermore, lines calls are extensively covered in Section 6, but readers miss that there is one aspect about calling your own ball out that is specifically covered in Section 13.D. In fact, the title of 13.D. is “Player Line and Fault Call Responsibilities”, emphasis on “Line”. And immediately following the title, one finds the rules for “Non-Officiated Play”, with the first rule , 13.D.1.a., stating “… players are expected to call any type of fault on themselves or their partner as soon as the fault is committed or detected”. The title specifically mentions “line and fault”, and the rule specifically states “any type of fault”, which includes lines. (And the section “13.D.2. Officiated Play.” has similar rules and wording.)