As far as I know NeoAC prevents long name crashes as well as some other protocol abuses, but those are only a few methods one can use to crash a server or otherwise disrupt the gameplay. Surely it's the best available method so far and I hope Mono gets to release future versions. I know its possible to bypass it and how to do it, but I've never heard of a program made specially to bypass it. If there is such thing then it's likely fairly recent. But technically you could use existing programs such as a packet editor to easily bypass it, if you know how to do it.