Excellent point. The easy alternative is to replace the checkboxes with selects which just have "Yes" and "No" as options. Not as clean from a UI point of view, though.

Yet another option is to set the values of the checkboxes to a unique identifier like the IDNum (assuming it is unique) and that way you know which ones are to be kept.

There's also the JS option, but I like that least of all.

TIMTOWTDI!