The OEM for the Audi windscreen is Guardian AFAIK. Pilkington might be second-line supplier, or for later/alternate spec models. Whoever it is, the long and short of it is that if the glass does not feature the four rings, it's not OE. So many in the trade talk about glass being the same, or that there is some little man at the end of the production line stamping logos onto the glass. Rubbish, and in fact, the aftermarket windscreens are usually not even made in the same country never mind same production line. Even when they are, there are differences in the manufacturing processes, so much so that when you ask the manufacturers (if both windscreens are equal) the kind of response you get is that both examples "respond" to 'main technical and aesthetic criteria'.
In effect what this means is that a
fake product 'responds' to the same aesthetic (it
looks the same as the original) and technical characteristics (it
does the same job as the original) so you can maintain a healthy interest in manufacturing for two sectors of the same industry. It's business.
Personally I don't see the harm in having a tier system, ie, a premium product and a budget equivalent. It exists with tyres. The reason it does not with windscreens is because insurance companies want to save money... and windscreen replacement companies want to be their chosen suppliers.
A footnote on the insurance policy wording:
Indeed although it does depend on your insurance company and their policy.
It does go back to what was accepted before the policy inception. In other words, when you ask for a quote, and the proposal states
"UNLIMITED WINDSCREEN COVER" most people will see it as an essential benefit however, if - and in accordance with ICOBS 6:1:5 (Insurance Conduct of Business Sourcebook) - a proposing insurer did,
"take reasonable steps to ensure a customer is given appropriate information about a policy in good time and in a comprehensible form so that the customer can make an informed decision about the arrangements proposed",
the 'benefit' would be worded different to state that in the event of a windscreen claim, the insurer has a preferred supplier who will be using non genuine parts.
I don't think insurers are doing enough, and many motorists only see the what 'unlimited windscreen cover' really means when they end up with a cracked windscreen. More on that here:
http://www.glasstecpaul.com/motor-insurance-windscreen-cover/