Counterfeit 20c cartones

As stated, given the cartones’ size and deterioration through constant use, it is not surprising that the ordinary person would be hard-pressed to recognise a counterfeit, but some egregious examples stand out, such as these examples from the Banco de México's collection^{V 49904 CNBanxico #3857: V 45629 CNBanxico #6661: Z 421901 CNBanxico #3853}:

for series V

and

for series Z