"I guess me parking there and not using their Bus would be frowned upon"
Interesting question. The answer should be 'obvious' - but isn't
http://www.edinburgh.gov.uk/internet/transport/parking/cec_park_and_rides
says
"Why try a park and ride?
Park and ride is a quick and stress-free way to get into the city centre. Park, catch the bus, and sit back and relax!"
That's straightforward; doesn't actually say you have to take a bus.
"Parking is free. Overnight parking is not allowed."
- so you can't use it as a long stay car park when flying off somewhere. But (perhaps) you could park and cycle to the airport for a day trip to London.
So I suppose the question is - 'do so few people park and cycle that there is no issue/problem - or if you park and cycle does someone jump on you and demand you buy a bus ticket??'
Perhaps it's officially OK - but not promoted because the car park gets full anyway.
You can't be the only person wanting to drive and cycle. I suspect you might even be willing to pay a small 'bus fare equivalent' fee. Certainly the Council wants to discourage driving into the city (especially at rush hour) and cycling.
There'll be an answer somewhere...
Meanwhile - http://citycyclingedinburgh.info/bbpress/topic.php?id=1092