Well when i enter siege i have the 14% stable buff, a 10% ride potion from the IS and my galloping gale, going through our left side to the opposing team left castle is very fast and i get the guards. If they had the 30% speed mount potion instead of the 10% i use, very fast. Also i always fully buff in siege, get 595K PDEF/ 90K PATK, 500K + HP etc, guess i should use egg rice and get honor gear to see if i would ever die loll.
The other issue you mentionned of not being able to rez while said players was on top of you, ya i got that from a guild, can't remember which one but never tought much about it, so much weird stuff is happening in siege that i do agree GM's should come and check it out. As to those who think GM's can't to individual siege, lol, they can. Make a toon, join a guild and join siege when it happens, of course when they have spare time to do so ;-), but doable and time consumming. I would say if they get more than 10 complaints against a certain guild/player, they should take the time to investigate.
I've been called a hacker because a knight should not have 100+ kills in siege, loll, i tell them to stack more PDEF and TP ;-) Don'T forget, it'S not because you are a rogue, a mage that you can kill every knight you encounter, some of us know how to play our toons. I have never switch classes, been playing my knight in siege since 2009 and enjoy it very much.
K/P/S/M/W 98/98/98/98/98
Disturbed guild leader on mithras 
BTW i do live under a bridge, i am Green, i can dish it out as good as i get
There are no better server than Reni, best place to be!!!!!