A rabbi, a priest, and a lawyer were all...
A rabbi, a priest, and a lawyer were all caught in a shipwreck. Naturally, there are a lot of sharks circling around. All of a sudden, one shark darts in and grabs the priest for lunch. No more priest.
The rabbi starts praying frantically, but to no avail, as a shark comes in and eats him, too.

Now the lawyer is really worried, as a shark is coming for him. But, miracle of miracles, the shark puts him on its back, carries him to shore, and lets him off.

The lawyer, curious, waits till the shark is far enough away not to eat him, and asks, "How come you didnt eat me?" And the shark replies, "Professional Courtesy!"

500 lawyers in the ocean
What do you call 500 lawyers at the bottom of the ocean?
A good start.