What is Apple's official line on hand-cut nano-SIMs?

I use local SIM cards whenever I travel and I never pay roaming charges. The downside is that I need to obtain a new SIM card for each new country that I visit.

Whilst many carriers now issue nano-SIMs, there are some who still don't or they make it difficult for prepaid customers. I'm getting a bit fed up with ordering or buying a nano-SIM (which should be 12.30x8.80x0.67mm) but receiving a hand-cut nano-SIM (which is 12.30x8.80x0.76mm), i.e. 13% thicker than it should be. Although 0.76mm-thick SIM cards can be forced into an iPhone 5, they don't go in easily and I've read reports they can get stuck so it wouldn't surprise me if this invalidates the iPhone 5's warranty.

Some examples of offending networks are:

• O2 Czech Republic - despite the advice on their web site, many of their shops use SIM-cutters to create a 0.76mm-thick SIM card for prepaid customers.
• LycaMobile and Toggle Mobile - one of the fastest growing prepaid MVNOs in many developed countries, with prices very suitable for short-term visitors to a country. If you order a nano-SIM, they send you a hand-cut 0.76mm-thick SIM card.

What is Apple's official line on using hand-cut nano-SIMs? It would be useful to quote a knowledgebase article to the errant carriers.