Why less emphasis on private data?

[Paul Rubin]

Steven D'Aprano <steve at REMOVE.THIS.cybersource.com.au> writes:
> > If you want to write bug-free code, pessimism is the name of the game.
> 
> I wonder whether Paul uses snow chains all year round, even in the blazing
> summer? After all, "if you want to drive safely, pessimism is the name of
> the game".

No.  I'm willing to accept a 10**-5 chance of hitting a freak
snowstorm in summer, since I drive in summer at most a few hundred
times a year, so it will take me 100's of years before I'm likely to
encounter such a storm.  There are millions of drivers, so if they all
take a similar chance, then a few times a year we'll see in the paper
that someone got caught in a storm, which is ok.  Usually there's no
real consequence beyond some inconvenience of waiting for a tow truck.

Tow truck or ambulance operators, on the other hand, should keep
chains available all year around, since they have to service the needs
of millions of users, have to be ready for freak summer storms.

As a software developer wanting to deploy code on a wide scale, I'm
more like a tow truck operator than an individual car driver.
Alternatively, as a coder I "drive" a lot more often.  If some Python
misfeature introduces a bug with probability 10**-5 per line of code,
then a 100 KLoc program is likely to have such a bug somewhere.  It
doesn't take 100's of years.