I was just watching FujiTV Sport and they mentioned that Akinobu Okada actually took out a home run insurance plan on Takahiro Okada (T-Okada) back in December. A Daily Sports Online article posted on 12/16/2009 confirms this fact.
Now why was that necessary?
T-Okada had hit a few balls out of the Secondary Skymark Stadium during practice and that got Okada worried about the possibility of an accident.
The insurance plan they signed will pay-out up to 100M yen for any incident that involves a home run hit by T-Okada causing an accident out past the outfield walls of Skymark Stadium. No word on the premium the club is paying in order to get the coverage.