It will never pass an emissions test.

I would expect it to constantly have a "check engine" light as the rear O2
sensor complained the converter was not working right.

If you are in the US, be aware the EPA fines for being caught doing that
would buy you several new Hondas or many dozens of catalytic converters.

Mike

What's the reason for doing it? Figure the cat's plugged or something?

The cat on our old '86 Toyota MR2 rusted out, so I had it replaced with a
pipe for a few months until we sold the car. There was maybe 10% increase
in exhaust noise, and no noticeable increase in power.

We got away with it because the computer had no idea if the cat was there
or not. Your OBD-II car will complain loudly when the ECU gets the wrong
signals from the downstream O2 sensor.

For what purpose are you replacing the cat with the straight pipe?
To save money by not buying a new cat,or for "more power"?

There ARE hi-flow cats available,and that would keep you legal AND your
OBD-II system happy.