Yes, that was definitely my thought too.
My daughter has a dynamic sort of like that going on now. Her very good friend Kay can be quite dependent on sozlet. Earlier this summer she was sending off 30 text messages a day before sozlet woke up -- "r u there??" "r u awake yet??" etc. etc. Then after that went on for a while, with requests to see sozlet pretty much daily, and the next level was getting very worried if sozlet didn't respond right away during daytime hours (after she was likely to be up). "Are you ignoring me? Are you mad at me?" Sozlet was OK with this but was starting to get a little impatient. That had a few rounds, then E.G. overheard Kay (when she was here) grilling sozlet about who her BEST friend was. C is a good friend, but Kay is her best friend, right? Sozlet wasn't completely conclusive -- C is in fact a very good friend -- but she said that she's known Kay longer so yes, Kay is probably her best friend.
Then some more things happened (this is already a bit long, sorry), as one example, sozlet was at home when two friends came over and asked her if she wanted to hang out with them. They then went to a block party where Kay happened to be. Kay wanted to hang out with sozlet but not with the friends -- sozlet wouldn't dump the friends who brought her to hang out with Kay. Kay took that as a purposeful dis, (even though sozlet went back to the party, alone, after her friends left just to find Kay, who was on her way out) and then the next day at the pool when they ran into each other Kay said she didn't want to hang out with sozlet.
To sozlet that was out of the blue -- I was happy for text messages in this instance so I knew context. (The messages go to our shared iPod, which Kay knows.) It's come up before that Kay's mom and older sister have advised her to branch out and find other people, and not be so dependent on sozlet.
Anyway, they seem to be mostly on speaking terms now (I still don't quite know what's up -- sozlet thinks everything is fine but I'm not sure if Kay does), but I can easily see that with just a bit of prodding from older sister/ mom, the relationship could've been cut off completely.