you are right - but with long drain interval oils which have a service life of 20,000 kms or so, you will see the level drop and then will be required to top it up. If someone complains on that - then they are ranting.
oil burn is bad and usually is accompanied by high usage like a litre of oil every 500 kms (thats really bad) - but if you lookup the normal oil consumption figures from toyota/honda etc, they claim that 1 litre/1200 kms is normal. LOL. (they say to to shoo away customers from bugging them to fix something)