Here is your answer to your own question as referred to in number 11 of the "In Game Rules" - No where does it say that people are not allowed to have multiple computer's playing the game. It does not require any "Software" to achieve this, thus it is acceptable. If anyone can find a way to NOT use software to load up multiple accounts on the same machine then that would be fine as well.
11. Users are prohibited to use any kind of the software which allows you to open several client windows simultaneously,
i.e. playing several characters at once - such behavior would result in account block without any possibility to revoke it.
I also believe that Trion has a setting in the Glyph client launcher that allows the use of multiple clients. Thus it's not illegal there either since they give you the option to do it.
Hope this answers your questions. Gluck =)