Let me explain a few other advantages these exists keys give you...
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You also see an ithizir scout(1), and an ithizir scout(2).
an ithizir scout(1) disarms you!
an ithizir scout(2) picks up your bloodstained death sword!
an ithizir scout(1) goes east.
an ithizir scout(2) goes west.
>west
You also see an ithizir scout(3), an ithizir scout(4), an ithizir scout(2).
{about 7 scouts go in and out}
>kill (2)
You recover your gruesome blade!
That situation would be impossible with the wiz data stream... you wouldn't know the position (other/third/whatever since some are moving in and out) or even which way to follow.
Code:
You also see an ithizir scout, and an ithizir scout.
an ithizir scout disarms you!
an ithizir scout picks up your bloodstained death sword!
an ithizir scout goes east.
an ithizir scout goes west.
>west (by chance)
You also see an ithizir scout, an ithizir scout, an ithizir scout.
{about 7 scouts go in and out}
>kill third scout
BZzzzT wrong, the scout is now "other" scout because of the ones moving in and out, you lose.
Hell the exist keys are consistent across players (just not across uh.. existance.. when equipment "logs out" with you, their keys get reclaimed), you could be dead and get looted, and then tell your friend "track down a scout with exists 839420, he's got my sword".
The SF doesn't even have to send "other/third" it can just send the exists key. I never use my mouse, but I program to SF because I want the extra info.
You could write a program that whenever you weigh a box, stores that exist key with the weight, then when you look in your container it could say: "a modwir trunk (12lb), a modwir trunk (17lb), a modwir trunk (38lb)".