Herman Grishaver:
Rowing in the boat with Jannie was Marianne (Nanny) Grishaver, who was also arrested - for not showing the Jewish Star. The girls had removed their sweaters which had the star on it. About 3 weeks after release, Nanny received notice to report to Central Station for transport to Westerbork. She did not go, but instead, about one month after release from jail, the Louis Grishaver family, also living on Amsteldijk (104) escaped with Nanny and survived the war, reaching New York City in the summer of 1943.
I found an account by Nanny's mother written in 1943 that says it was not legal for Jews to be boating on the canals, and this was also a reason for the arrest.