multi-boxing is the playing of multiple characters at the same time. You can have all the characters being played at once as long as your not using broadcasting software to automate the ‘extra’ toons your good.
This here shows that there is no hardware restrictions currently from a blue. So saying that hardware solutions should be fine and considering they literally said the only no-no is IB software I think ‘should be fine’ is a reasonable statement.
Using a KVM switch is the first hardware solution i can think of that would probably pass muster. On that note there is a few other cheaper and easier solutions that the multi-boxers of old used that are possible as well such as windowed mode and clicking through everything / using macros. Please also note that it costs a bunch more money to implement a hardware solution so most people wont go that route though and that is more important than anything else for limiting boxing. shrug