Can i get banned from Garry's Mod somehow, if i use leaks?

I don't think so, but I'm not familiar with it so I prefer to ask

[ps: I don't use leaks! and hopefully i don't have to do it in the future xP]

the case looks like this when using an addon from leaks, you will not be in danger because no one has how to check whether you have purchased the addon or not
also you have nothing to worry about.

Okay thanks!
But I think I won't do it anyway ;P

You wont get banned from the leaks cause since gmod havent got anti cheat if you are using it on your server with your mates that Completely finebut if you making a server that is public that going to be a problem cause if the dev comes on they will report you and block you as well

I used leaks and never got banned when IO played but I stopped like a year ago!

There isnt really a way to check if you bought the addon or not, if the addon doesn't have a 3rd party checker that is. But you should be safe using leaks. (Dont take my word for this, i am simply stating my opinion)

no but if the community finds out your server will be insulted

https://wiki.facepunch.com/gmod/Server_Operator_Rules It doesn't say something like leak use is forbidden here so don't worry anything happens

You wan't be getting banned, the only thing you have to worry about is backdoors etc....

No you can't get banned. If someone has a backdoor they could access your server though.

Hope this helps