I've owned my IC-7000 since 2007 and never heard of this! Mine has spent its life on a series of AC powered supplies that are off far more than they're on (on a yearly basis). I know there have been times when the power supply was off for a year or more and I've never seen any evidence of the radio forgetting anything.
What does the small current keep it from forgetting?
W4ATM - 35 Miles south of the Kennedy Space Center
Retired RF Design Engineer
Now able to play with all the hobbies I never had enough time for