It's common for our facility to receive product from the field that obviously has not been cleaned, even perfunctorily. I'd say that is more common than to receive cleaned items.
And, even if a returned item appeared clean and came with a certification of sanitation, how do you know that the sanitization was effective?
What are the consequences to your business operations if it's determined that your facility, or worse yet some shipped product, has been contaminated via some accidental indirect contact with something that came in from a user site?
At my company, our procedure assumes incoming product from user sites is contaminated. We assume that that product has not already been sanitized irrespective of what we've been told, and sanitize it before any further actions are taken. Until sanitization, we control contact with that product so as to avoid secondary contamination.