If you blacklist someone, they can't join your GAs and you can't join theirs

It is not written in the rules

It is not written in the rules

It is not written in the rules

How does a blacklist work?
It's important to note that blacklists work two-ways. If you blacklist a user, you will also no longer see their giveaways on the homepage, and you will not be able to view or enter their giveaways.

https://www.steamgifts.com/about/faq

How does a blacklist work?

On user profiles, you'll see a button with a circle icon and a slash through it in the left column. Clicking that button will add the user to your blacklist. Clicking that button again will remove the user from your blacklist. When you blacklist a user they will no longer see your giveaways on the homepage, and they will not be able to view or enter your giveaways from that point forward. If the user entered one of your giveaways prior to being blacklisted, their entry remains valid.

It's important to note that blacklists work two-ways. If you blacklist a user, you will also no longer see their giveaways on the homepage, and you will not be able to view or enter their giveaways.

Here's some more info from when the change was implemented. You will not be able to enter their giveaways as soon as you remove them from your blacklist, there is a delay for up to a week depending on how long you have had them on your blacklist.
https://www.steamgifts.com/discussion/uWdUq/two-way-blacklists

OK

I wonder how many people will BL you after creating this "It's not written in the rules" discussion?