Resolution [for sent coins] too large in common Bitcoin sites [Superman III]

[realnowhereman]

Mt.Gox and MyBitcoin (at least) both seem to limit Bitcoin transfers to two decimal places.

I don't mean to 0.01; I mean that you can't send 100.009, you can only send 100.00.

Doesn't this create a Superman III opportunity for the site owners?  As it's impossible to ever get the fractions of a cent out, they can aggregate them and do what they like with them.

I'm not saying they are doing this, but it shouldn't even be possible.

(edit: better title)