Mind it was 100Km/h not mph. I'm not sticking up for them but it looks like a big wide road with 2 possibly 3 lanes.
Don't know what the VW seatbelt warning is like but if its anything like my Mazda it goes off after 60 seconds.
I ran back and forward the quarter-mile to the village shop yesterday, twice. (Had to take the car because there's a limit to how much cat food, milk and bags of fruit I can load on my bike!) The twice was because I forgot my wallet. Frankly, I don't bother with the seat belt for that trip, 2 minutes at less than 20 mph.
Second time of travelling, the musical pinging to say I wasn't wearing the belt didn't happen. Don't know why. The dashboard display was lit up, though.
Rolfe.