Check. The. FAQ.

Lary Over の投稿を引用：

VAC?

FAQ!

Kwerz の投稿を引用：

You sure about that ?

Yes.

Kwerz の投稿を引用：

without any risk or ban or sanction ?

Yep, don't worry.

http://psteamcommunity.yuanyoumao.com/groups/idlemastery/discussions/0/152392786912268315/

Same as VAC
http://psteamcommunity.yuanyoumao.com/groups/idlemastery/discussions/0/152392786912268315/

https://psteamcommunity.yuanyoumao.com/groups/idlemastery/discussions/0/152392786912268315/

yue (´・ω・｀) の投稿を引用：

Is there a way to make the "hours played" in the games not build up while using this program to get the card drops?

Nope, it's impossible.

Gampsoplocedromeus | Gamdom.com の投稿を引用：

it's not good :(

Why? Just imagine so you can get cards from nowhere and can endlessly repeat it - their price would be $0.00

Gampsoplocedromeus | Gamdom.com の投稿を引用：

And if I sell a crad, can I idle that again?

Nope.

For every $9 USD spent (approximate) since the start of the Steam Trading Card Beta, you will earn one card drop (CS:GO, TF2, Dota etc).