It's a can of worms. :)
Here's what's happening:
First, when you perform @arrayA ~~ @arrayB the action you get is actually similar to ($arrayA[0] ~~ $arrayB[0]) && ($arrayA[1] ~~ $arrayB[1]) && .... So you're really getting a chain of scalar to scalar smartmatches.
Next we have to scan down the list to find something that fits the description of 'scalar ~~ scalar', while keeping in mind that the lefthand side looks like a string, and the right hand side looks like a number. Here's the obscure rule:
Any ~~ Num: numeric equality
like: Any == Num
(~~ added for clarity)
So you're comparing something like this: '1ringydingy2ringydingy' ~~ 1. The righthand side is a number. So a numeric comparison will be performed. And what happens when you use "1ringydingy2ringydingy" as a number? Well, if a string starts with a number, Perl will use that number and drop the rest when performing numeric operations. So '1ringydingy2ringydingy' ~~ 1 is the same as '1ringydingy2ringydingy' == 1, which is the same as 1 == 1.
