This would be a no from me. I see no reason to leave a message. I can turn stealth on and off. If I have stealth on, I am probably warring you and I really don't need to give you a reason as to why I attacked you. You are in the warbase.
If I attack you for another reason, I will have my stealth turned on if I want you to know it was kme who kicked your ass. And if I did that, I probably did it for a good reason and would welcome the whiny mail about it in my mailbox.
Apart from that, I foresee mayor abuse in this plan of being able to leave a message.
How about posting stealth depends only on dexterity, as does anonymity during attacks? If you're good enough to qualify for attacking stealth, you automatically qualify for posting stealth unless Ofcourse you have kept stealth turned off!
Education would make it unfair for newer players attacking newer players who want to leave a message anonymously
Hiring for 5* Sweet Shop! Hiring all stats! Follow the rules and make 500k-700k a day! ALL STATS!