Anyone can make a mistake, but an oil change only has a few mistakes that can be made. If you can see the filter you can see it's been changed. If you can pull a dipstick you can see it's got new oil and has been refilled to the right level.
So with my 211 being electronic level and no reusable dipstick I get my trusted garage to change the oil, not Kwik Fit. Otherwise I would.
I have personally experienced going to a garage (Vx main dealer) with a Zafira for a service, and making note of the parking bay it was in then picking it up on the evening and a few basic checks (cold engine, dirty oil, incorrect tread depths on the survey sheet, still in same parking spot) showed that it hadn't been moved. Main dealers are as tricky to judge as anyone else.
A friend (years back when Halfords did servicing) dropped his prelude in, a simple mistake in procedure lead to...
1. Put waste container under car
2. Remove sump plug
3. Wait for oil to drain
4. Add correct amount of new oil as per book
5. Replace sump plug...
It drove about 4 miles towards home...
So since both of the above I check, every time, but the 211 has no dispstick...