Also no. All these ideas start from the base premise that pushing solo players into open is good. As it stands now, people play in open, solo or private groups depending on their preferences. That seems like the best possible scenario.
Maybe the game will attract more players that want to run around in open with you, and maybe it won't.
It isn't an unmitigated good to transition players from one mode to another, doubly so if you implement it via pressure. Just like it isn't/wasn't good to have players feel forced to trade to make money, it wouldn't be good for players to feel they have to play in open.
I wouldn't say the goal is to push people in any direction per say - isn't the idea of an open, dynamic universe appealing to you? Something that simply without the human element couldn't, and does not truly exist. Even if it does attract additional people, isn't that a good thing? And it's not hurting anyone in Solo. I can't see any reason not to implement a 10% bonus to people trading in open.