There won't be a problem as long as you bring them back a core & not a rock.
They know that a few will be unrepairable, & if yours happens to be in that category, then there was no malicious intent.
I worked in a parts store when in high school & we ALWAYS opened the box to make sure there was a part in there. We never checked the condition.
They can rebuild almost any caliper though.
I admire your desire to be honest with them though.
