The creator of the Idle Master itself advised against using it on a VAC server, because it actually has a chance to trigger the VAC program.
So its very possible that it could trigger a VAC ban while running steam related programs even if they don't affect the game at all, because it was built that way. A Fish Called Wanda is a 1988 heist comedy film directed by Charles Crichton and written by Crichton and John Cleese. The problem being that VAC doesn't always differentiate between malicious 3rd party programs for cheating, and non-malicious 3rd party programs like Idle master or steam achievement manager. Since you used Idle Master, The VAC server triggered a suspicious activity on your side and you got kicked for 7 days because of that. This is Idle Master thankfully, and i don't think i have seen a case of someone being VAC banned because of it alone. Even if you were using a completely harmless program like idle master, if you ever happened to get a VAC ban because of that, then the majority of people including steam support will not believe your case, even if its true. Please never ever use 3rd party software programs again while playing on VAC secured servers, THAT is the silly thing to do. You will permanently have that VAC mark and won't be ever able to justify in removing it, because your honest reason of it won't have any credibility since its easy to fabricate excuses like 'I was just using a script or a non-harmful program'.
