I opted out of "pre-screened" offers years ago, and I think that has helped a lot. I did the "permanent" version, but there is a 10-year one IIRC (at least when I did it).
It seems like they could just get everything about you. Total and complete identity theft
EDIT - can't get the form to submit without an error anyways. We're sorry!
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Same thing happened to me. I just refreshed the page, confirmed form resubmission, and it worked.