In VW camper we always wave at othe CVs; any model VW always wave back but the bigger non-VW campers rarely seem too. Pity, cause the mutual wave leaves both parties happy, surely?
A chap I worked with had a VW camper van, and he always said that from the natural seating position a wave to another VW usually looked like a Nazi salute!
Regards Alan AP08 MOG 2016 Plus 4 GDi - Mazda Soul Red Metallic