Doesnt make any difference what they put in the "Whats this for" field.
ALL Paypal can be reversed up to 180 days, period.
That doesn't mean they get to have the money back, just that they can file, up to 180 days, for a charge-back.
And if you do not have the 'proof' PP wants, or the word 'bitcoin' is mentioned by either party. you will lose.
Anybody that says otherwise is prob a scammer who wants you to take it.
Please don't take my word for it. Come to
www.bitcoin-OTC.com and there you will find 600 'live' users who will tell you the same thing.
B Good