The issue is PayPal rules are arbitrary and a scammer is going to know how to use them to his advantage is both directions.

For example if a noob pays by gift using a PayPal account with a balance he likely is screwed.  So never pay by gift (you can also get banned simply making too many gift payments).

Oh so gifts are safe to accept right?
No absolutely not.  A scammer is going to be more than willing to pay by gift using:
a) a hacked account - auto reverse you lose
b) claiming his account is hacked - auto reverse you lose
c) a $0 balance PayPal account where tx is funded by CC - charge back on CC -> reverse on PayPal.

PayPal requires completely and absolute trust because it can be used to scam both ways.  For example FastCash4Bitcoins uses PayPal payouts but you shouldn't use our service unless you already trust us. 

Sadly no matter how many times this explained people seem to get scammed.

TL/DR:
Paying by gift to an untrusted persons = dangerous.
Accepting payment by gift from an untrsuted person = dangerous.