Well said, that it's very beneficial for both sides... I see the biggest problem in actually knowing what the "official channels" are. There're no contacts, just usually nothing to start off with.
I sometimes try to go for a cockpit visit when I fly somewhere, so ticket purchased on the normal price, nothing out of order. The most difficult thing is to find the person responsible for arranging the visit to the cockpit.
Pilots usually don't know who is that person, sometimes they don't even know their OPS' phone number... An IBE pilot gave me the phone nr from the website to try to contact OPS - after half an hour of listening to options I gave up...
Our managers are not really interested in arranging these visits, they have their own things to do, I don't blame them for that. It's not a big issue to write an email or to call as long as we know who...
At least I learned something today - I didn't know there was such a thing as ATC liaison officer at an airline... Is that common?