There is an ignore function for trade and for PM.
The PM ignore function was add by
MA after long whining from player , still , the function exist now.
There is 3 icon on the top of an PM window , close, reduce,ignore.
The ignore button ask for an confirmation , and you wont get any pm for that person until you relog.(the relog reset to zero was asked by player too , because sometime in first age , som people ignored friend on mistake or for test purpose).
The ignore for trade exist since very very long time , but i dont remember it ever worked.i remember like 2 year ago
MA in som VU after the new trade system(the on used now) say they fixed it , it still not working.