These players tend to be really adamant about going to the lanes because that's all they know how to do. I mean if you look at the match history of these people you'll see that they've been playing that champion ever since they were level 10. It's uncomfortable being put into a new role. My solution is to just learn more roles since it's necessary in ranked level 30. It's good because it increases my knowledge of how each lane plays so I can prep for junglers and know how to synergize with others whilst improving my overall skill.
It would be nice if people were to ask to play a crertain role yes but in the interwebz you wont find that a lot of other people really actually give a s^!&.