Yes, this could occur, however, the odds of it occuring diminish quickly the more items you have
Here's a little script I did up to get the numbers accurately (or at least as accurately as mIRC will display them) in a percentage form
alias comb {
set %a $iif($1,$1,$$?"Number of items")
set %c 1
while (%a) {
set %c $calc(%c * %a)
dec %a
}
echo -a $calc(100 / %c) $+ %
}
Note the above code presumes that only 1 item is being picked at a time.