Proper tire maintenance

[Jay2TheRescue]

Yes, an arrow on the sidewall indicates that the tire has directional tread, and the arrow needs to point counterclockwise.

[JockoT]

Originally Posted by Jay2TheRescue

and the arrow needs to point counterclockwise.

On the LH side. Clockwise on the RH side.
It has to point in the direction of travel or towards the front of the car.

[MechanicCat]

She is maybe less crazy than she seems. Just maybe. If you can inflate bike tires with CO2 cartridges, you can do the same with a car tire. Doesn't mean you should, especially at a gas station, where you can get it done in a more conventional way.
I actually saw a video of two guys from Poland destroying tires with two types of extinguishers - powder and plain CO2 https://www.youtube.com/watch?v=0yfXYOyZXEs
I don't see how CO2 can hurt the rubber in any way actually. But if she is using a powder extinguisher, which I doubt, she needs to replace the tires ASAP.
She is lucky it didn't blow in her hands though. Handling condensed gases like that is dangerous.

[JockoT]

CO2 extinguisher is exceptionally cold. The horn freezes when you use it. Most good tyre fitters in UK now inflate the tyres with dry Nitrogen.