It's not IL law, it is a RESPA requirement. It's buried in the instructions for completing a GFE:
Appendix C To Part 3500 —Instructions for Completing Good Faith Estimate (GFE) Form
Where a loan originator permits a borrower to shop for third party settlement services, the loan originator must provide the borrower with a written list of settlement services providers at the time of the GFE, on a separate sheet of paper.
David J Mulkerin, CRCM
All opinions expressed are mine and not those of my employer and are not to be taken as legal advice.