I have an acars program custom made for me, I dont require pilots use it, it is a bonus. A lot of the members are nor even 18 yet, and are still thought submitting valid pireps even when they file it manually. I think it depends on who runs the VA, and how it is run. If you do not put too much strain on the pilot, like having to file 5 pireps a month to stay active, even if they file manual pireps, they will submit an honest pirep. Also you need to know what is a true flight and what isn't, by actually flying them yourself. So lets say for excample, someone flies from New York to London, most VA owners know it should take around 7-8 hours, if someone comes along and files a manual pirep claiming to have done that flight in 15hours, then you obviously know it is a fake pirep. You can give a +/- 40 mins on top of what it would be if you had the perfect weather, and a direct route. I have seen very strict VA's where you can only fly online, which is good, but the fun factor goes down a lot. Also those VA's are only for the hard core advanced simmer, not for a novice. It is a delicate balance between realism and a fun filled hobby site.