Make any laws or regulations too onerous and some will be even more disposed to finding ways to circumvent them, or will just plain ignore them.
I have long weighed up the cost of compliance (in non-aviation matters I hasten to add) against the likely fine if I get caught. 99.9% of the time it has worked, and on the .1% of other occasions I have quite cheerfully paid the fine, knowing that I am ahead. Every one who exceeds the speed limit is doing exactly this.
Example: A tree is a nuisance, maybe a fire hazard. But if you apply to have it cut down, the authority says it is protected. Better not to ask, because if you now go ahead and cut it down, a nasty judge could send you to jail (stupidity being a jailable offence). However, if you don't ask, and do cut it down there's a good chance no-one will give a rat's. Worse case, some greeny dobs you in. So - even with a fine - problem solved, the tree is next winter's firewood now. You win all round.
Go go ahead - stop drill that crack, fit that non-OEM part, splice that wire. Just don't ask if it's OK and don't mention it anywhere. In keeping your aeroplane airworthy you may be committing an offence, but what are the chances of CASA actually determining when or how the work was done if the defect has clearly been attended to?
The 'S' in CASA does not mean 'safety' but 'short-sighted'. Or maybe good old 'stupid'?