I suspect Siege is still a hack-fest these days. We were sieging the other night against a guild where certain players couldn't be targeted, mages that could "see" rogues in hide from a distance, and every single guild member was port-lagging. Who knows what the cause was. This from a guild that had over 25 people against our 14. It could be purposeful hacks, or just a game crash, or simply bad lag. Complaining about it is pointless since we don't see action taken by the game administrators.
Honestly, it happens so often now, I don't really blink, though I am against cheating in any form. Sadly, its the norm in siege, but it makes beating guilds that cheat or appear to cheat that much sweeter of a victory.
Again, some effort in making siege better and working out all the bugs would go a long way to level the playing field. Hopefully that will happen someday, since siege seems to be a very popular event.
We sieged a guild with a good ol battlemonk last night.
I popped an invis pot, with intent to run past him, get behind him to attack.
As I went to move, with the invis pot on, he made a b-line for me, then targeted me and hit me with Fighting Spirit Combination.
Hacking is indeed alive and common in siege
Also, as a side note... Nearly 1000 replies to this thread now. The European side has about 950 replies to their similar thread. Id have to say to Frogster... its about time you send this MASSIVE amount of customer feedback to the developers so some of these issues can be resolved.