Can't say I've seen "hacks", but in the past 2 weeks I had 3 occasions, when enemy players in warzones, which were down to 20% or less, suddenly had "lag".
Means I can still see them, but not target them or use skills on them.
They stutter around in a some 20 meter degree.
I find this very strange.
Overall the connection quality (at least here in Europe) is getting lower and lower, but these "lags" seem "too convenient".
I hope its me just being paranoid, otherwise this great game will share the fate of so many other great games that died because of hacking(RIP Phantasy Star Online).