Hidden text.

[Mark London]

Hi - These days, how often do spammers at additional random hidden 
text?   For example, I found a ton of extra text at the bottom of an 
email, that was hidden by the following HTML:

<div style="font-family:Cambria, 'Hoefler Text', 'Liberation Serif', 
Times, 'Times New Roman', serif; width:1px; line-height:0; overflow:hidden">

Is this a common enough spammer technique, for me to write a rule to 
test for it?  Thanks! - Mark