So I woke up and immediate had this thought since i have played Stardew Valley quite a lot. So as far as I know Marlon doesn't like people going in the mines without some form of protection. He know how dangerous it could be. So you as a character are given a sword to help defend yourself. Now when you get knocked out in the mines I have found that you are picked up and brought back to the start level by one of three people and that is Maru, Robin, or Linus. Now this is where the Theory Kicks in What if the reason they are the only three that come and pick you up is because they too are members or the guild? There is no surefire way to check who is in the guild when you go to the guild hall. Robin and Maru would probably go into the mines all the times for their own purposes. Robin knows there is wood, hardwood, stone, and even clay in there. And you never see her really get anything for her own projects unless she takes what you give her for it. Still, there seems to be a purpose for her. Maru is a freakin' scientist, she would take the chance to study everything she could. However with the Danger that is present they would be constantly need protection. This is where Linus comes in. He is older and rather rugged for a "homeless" man. I recall him stating he wanted to be homeless. Still this means he has to know how to survive especially if maybe one day those little creatures in the mines decide they would not be there anymore. It's pointed out in the wiki and in several of the games festivals and event days that Linus will hang out with the Wizard. They are friend so perhaps he is getting training on the side as well. Thus when robin and Maru bring you up they go and get linus to take them down into the mines and protect them. And when Maru or Robin are the ones you wake up to it's clearly during the times that Linus is being a Badass and protecting them from a possible shadow brute or something as they are trying to save you. And when it's Linus that brought you up he was simply in the mines from training purposes. This would also allow them all access to the mines if Marlon knew that Linus was able to protect them at all times. And he is only willing to protect him because they don't give him a hard time for living on the hill behind their house. Even during the Eight heart event for Linus. The farmer could ask Linus to move in on the farm and Robin would be super excited to build an actual home for him. So I think he protects the girl due to not them being girls but because they aren't really bothered by him
except robin is afraid of linus and clearly doesn't know him well. i could see her utilizing the mines but i'd think it would be more maru(who is a nurse) or demetrius(who is a psudo geologist) going down there and her just asking for stuff to be brought back
Ah but Robin isn't scared of Linus in fact she doesn't mind him so long as he isn't a bother to her and her family.
in the heart event where you can offer linus a place to live she is so visibly startled by the sight of him she jumps
Interesting theory. One of CA's many positive characteristics is the way he's sketched in characters and events, while letting players fill in all the details. Another theory that's been mooted about suggests that Linus is involved with the jumino, and desires to see you succeed both on your farm and, more importantly, reclaim the Community Center. So it makes sense that he would rescue you from the mines, rather than leaving you to become Adventurer Pate (maybe with a nice Chianti) for some Squid Kid.