..What they will mostly do is instead of making a whole transaction worth 10,000 they will just do two 5,000 transactions in order to remain undetected. ...
Regulators are well aware of this phenomenon.
The practice of splitting up transactions into smaller transactions in order to bypass
reporting is called Structuring / Smurfing.
https://en.wikipedia.org/wiki/StructuringYou will not go undetected if you try this, because banks are also obliged
to report Structuring / Smurfing in most countries in the world.
E.g. they might not report you for making a transaction above the threshold, but they
will report you for suspicious activity, which is even worse for you as a customer
than the standard reporting.