One of our cars (daughter's SEAT Ibiza) is on an EMaC operated plan with LC Charles SEAT in Crewe. I was aware of the risk, but for her car it's not a huge amount of money (£15/mth for 20mths covers 2yrs servicing and MOTs). This is for years 4 & 5 of the cars life, the first 3yrs were on a VAG contract. 4yr service is a major one.
I did have a problem with the way it works though in that it's quite clearly a scam to get you to go back to the dealership. I was particularly miffed that I had to pay extra for the brake fluid change and the service manager even agreed that it was part of the service schedule but still wouldn't cover it. Despite them having just done a major service, they then failed the car on its MOT (this is at 4yrs/34K miles) on a couple of dubious points that, of course, they could quickly repair in exchange for £200 or so.
This has cost them and SEAT (SEAT UK think it's fine for the car to fail its MOT) a new car sale - daughter likes her Ibiza and would be glad to have another, but I'll be directing her to look elsewhere.