Brian,
See "Additional Notes and Losses" for
1. Seenotstaffel and
2. Seenotstaffel on the
Luftwaffedata Wiki
The
2. Seenotstaffel notes will give you an idea of their operations.
These are derived from RL10/401 and RL10/402 respectively. Neither these nor Larry's notes indicate anything like your suggestion of impunity....
Note even though RL10/401 indicates that it covers from July 1940 there was little for Aug and Sep 1940.