Null is evil. However, the lack of a null can be a greater evil.

The problem is that in the real world you often have a situation where you do not have data. Your example of the version without nulls can still blow up--either you made a logic mistake and forgot to check for Goodman or perhaps Goodman got married between when you checked and when you looked her up. (It helps in evaluating the logic if you figure Moriarty is watching every bit of your code and trying to trip you up.)

What does the lookup of Goodman do when she's not there? Without a null you have to return some sort of default customer--and now you're selling stuff to that default.

Fundamentally, it comes down to whether it's more important that the code work no matter what or that it work correctly. If improper behavior is preferable to no behavior then you don't want nulls. (For an example of how this might be the right choice consider the first launch of the Ariane V. An uncaught /0 error caused the rocket to make a hard turn and the self-destruct fired when it came apart due to this. The value it was trying to calculate actually no longer served any purpose the instant the booster was lit--it would have made orbit despite the routine returning garbage.)

At least 99 times out of 100 I would choose to use nulls. I would jump for joy at note to self's version of them, though.