I thought it was unwise to push/roll start a car with cats.
It's always advised against in owner's manuals but for no good reason, IMO. Push starting a manual car is no different from cranking it using the starter motor except the gearbox is turning the crank rather than the starter.
Obviously if the car consistently fails to start you're going to soak the cats in fuel, which is a bad thing, so I guess they're working on the assumption that you've already cranked it until the battery's flat, at which point you should really figure out what's wrong.
If the battery has gone flat because it's old or because the lights were left on there's no problem with a bump start, IMO.
Batteries tend to give quite a good warning before they die
My experience with "maintenance free" batteries is that they die suddenly. I've had 3 battery failures in the last 10-15 years or so. All 3 left me stranded with no warning. On one occasion, I pulled into a motorway services for a coffee, went to restart and the starter motor kicked once then all the electrics died and the alarm went off. Battery totally fubar.
I guess now I've got an auto I should keep an eye on my battery
Kevin