This may be an issue with people with limited steam accounts, people who have steam communitiy bans, trade bans etc even though they are not VAC banned. A community/trade ban should not affect your ability to play games but it appears to do so in DayZ (unless it's just a coincidence) https://support.steampowered.com/kb_article.php?ref=4312-UOJL-0835
For example, we can see here that this ticket author is community banned. http://www.steamrank.com/#!/profiles/76561198084952625