why is s-u-b-m-i-t-t-e-d a banned word here?

i thought i just had a bad typo the other day when I tried to say "I s-u-b-m-i-t-t-e-d my 485...", but apparently it is not just me...

所有跟帖： 

• This is to avoid computerized attacks from that action -拖拉機手- ♂ (0 bytes) () 06/16/2010 postreply 09:36:59

• i see. many thanks! -000003- ♀ (0 bytes) () 06/16/2010 postreply 09:59:15