This is easily fixable: just declare I"P" to be not property, at least for this purpose. You already don't pay any taxes for holding it (which would fix some obvious copyright abuses).
This would leave physical property, services and financial operations as means of shifting cost.
Physical property is easiest to check: the company would need to ship a constant stream of one-sided widgets. These have obvious value: selling a box of screws $1M a piece is obvious fraud. Purchasing no end of usable wares at no more than 20-30% loss for 90% of the company's revenue, year by year, is not something reasonably doable.
Services mean the wealth is actually created overseas.
Financial operations are the hardest to oversee reliably, but if you skip all the creative accounting and look at the total net of money moved around, then again, shifting 90% of the company's revenue year by year is not something easy to hide.