No, the IRS will want to match the 1099-MISC and see it on your return.
The IRS requires the EIN number (or social) be reported on the 1099-MISC. If they don't want to use their social, tell them to get an EIN.
I would advise you mail the return in with the 1099-MISC.
You can enter the amount as cash. If the IRS questions it, they may agree with the way you decided to report it; however, not alarming the IRS is better than alarming them with an explanation. Even with the income reported as cash, the IRS will inquire about the 1099-MISC.
