That boat isn't going to get a ticket. He can LEGALLY park right next to the dive float.
California law doesn't really say much about dive flags. See:
http://www.garlic.com/~triblet/ba_diving/diveflag.html
I don't recall ever seeing that boat diving before. It may just be a newbie boat owner
being conservative. Not a bad idea -- do the first dive somewhere you can swim to
shore if your dive ladder (or lack of one) doesn't work out.
And there are other legitimate reasons to, with care, park there. I've parked the
whaler about there to support a club "tune-up" dive. Come in slowly, watch carefully
for bubbles, and help folks sort out their weighting.