Hi,
When you say strip you wan't to say striketrought?
If is that you want you can do that with conditionnal formatting (you
can only hide the checkbox), validation rules(you can show an error
message and surround of red your checkbox).
But if you want really striketrought you can only do that with the text
of the checkbox. For do that put your checkbox text in an xpath
expression ("your text") and add a conditionnal formatting (this time
you can use striketrought).
++
Thierry