I haven't played for quite a few months but i do have a lot of accounts.
The rule was imposed in a period with a few cheaters that created accounts every minute. We have created that rule, forced as requirements to complete trainings and that's good in a way, but bad in others. Nowadays we don't have all those issues and even if i like trainings i do think they make us loose more players because not everyone that starts playing the game don't want to spend time training, they just want to shoot people.
Not being able to play undercover so that others don't known them is also bad, imo, i did enjoy to play without none knowing you i was, i could spectate possible cheaters, i could play freely and it felt good.
I do realize this is my opinion and many others may disagree with me, just stating that second or third account not always have to be bad... Maybe with the release of the public background tool, one day, will solve this