erm
did i get this right?
any guardian can switch to zerk - at any level? w/o changing city alignment? w/o losing faction with the city factions?
well, i think i will stay guardian - maybe i just like being the only one around ^^
if switching the class is really that simple (or even possible) you will see the number of guards decreasing in no time ^^
an additional question: will a "betrayer" be able to betray again .. and again and again ...?

some more clarification would be nice i think