I worried about the radio anti-theft on my 560SL when I took my radio out for the first time. But after reading the manual carefully, the anti-theft only kicks in when the radio is removed with the alarm turned on, i.e. doors locked. I have disconnected the battery many times and removed the radio many times and never had an issue with the anti-theft system.

__________________
Len
'59 220S Cabriolet-SOLD and living happily in Malta
'83 240D 351,500 miles original owner-SOLD
'88 560SL 41,000 miles - totaled and parted out
https://sites.google.com/site/mercedesstuff/home
'99 E300 turbo 227,500 miles
'03 SLK320 40,000 miles - gave to my daughter
'14 Smart electric coupe 28,500 miles
'14 Smart electric cabriolet 28,500 miles
'15 Smart electric coupe 28,000 miles