When SMI is terminated erroneously, an individual is in approximately the same position
as the person whose enrollment was not processed timely. That is, the individual does
not know whether he/she still has SMI. Thus, he/she may enroll in other health insurance
to ensure some protection against medical expenses, or may defer necessary treatment
because of uncertainty about being insured against the costs of such treatment, etc.
When the error is finally corrected, it would be unfair to reinstate SMI entitlement
retroactively, which would require the individual to pay premiums for past SMI coverage
that he/she was unable to use at that time.