In WA, the cops will instantly sticker the car if you have wheels and tyres that don't match whats on the placard in the door sill. Hence if upgrading to 20's get a HSV tyre placard and run correct tyre sizing, anything out of the stipulated tyre sizing in the door sill will give you a instant defect, no questions asked. Running 22 inch wheels on a VE in WA, is the best way to draw unwanted attention, and get a defect.
It's an ADR rule, which I quoted....And ADR stands for Australian Design Standards....Last I looked W.A was part of Australia, so a little research on your behalf would be enough to show the W.A police are barking up the wrong tree. And once you have obtained the necessary information, keeping it in the glove box is enough to prevent a defect
BTW the old rule of thumb used to be 2" up on the maximum factory size, with a maximum of 25 or 26MM increase of track, from the widest factory option....However, this rule was thrown out 10 or so years ago.
Wheels and tyre increasing is the only thing, that springs to mind, that is uniform across Australia, when it comes to what is acceptable, without specific state rego approval. ie, the increases I mentioned is Australia wide and don't require specific approval by your state rego office,....If you were to increase your engine capacity, each state has a different view on what is acceptable and what isn't....
The only thing they could possibly defect you for, when going by the placard is load ratings of the tyres....If you have an HSV placard fitted and you fit 19" tyres, or 22" tyres, a good change the load rating will be lower than what the placard stipulates....However ADR rules stipulate, replacement tyres fitted must be of equal or greater load rating that what the compliance plate stipulates.....
So I would strongly suggest researching a little further into this before commenting further....The police seem to be dictating on something, that they obviously have no idea about and by you having the right information at hand, from the relevant authorities, will be enough to keep you defect free