Need some help with complexities of Facebook

[voluptuagoodshag]

I have a personal page and another page for my crafty business. When I set it up I invited my FB friends to like it. As far as I understand they got a message stating just that and they could accept or decline.
Another FB friend has a personal page and has just set up her business page but I get a message that she has added me straight on to it. Nothing to accept or decline. It is not something I'm interested in so have unjoined the group but am curious as to how this all works. I dislike being added to things without my say so.

[voluptuagoodshag]

Actually just rechecked, it was a 'secret group'!! Not sure why it has to be secret as she was selling make up but am still wondering how I can be added. I could be added to all sorts of secret groups and sects

[TennesseeMountainPointOfView]

Secret means it can't be searched and the only people who can even see that the group exists are current or former members. Former members cannot see who is currently a member of the group, only current members can. You can be added or invited by an existing member, but you can't make a request to join.

This is different to private groups, which can be searched for and people can ask to join. They can also see who else is a member.

Secret groups are better for avoiding spammers.