Unclear if this has already been thought of, but this would only be to prevent fraudulent fg purchases.
I have thought of two options, both involving email confirmations. I've been a vendor before and have won many disputes with chargebacks using a variation of the first method"
Have a confirmation email (receipt of payment) be sent to the same email that is registered to paypal with a temporary fg password (linked to the confirmation email):
Step 1: mungoflago buys 100 fg via paypal
Step 2: mungoflago receives a confirmation email stating "thanks for purchasing fg, your new temp fg password is mungorocks123; please understand using this temp password confirms your receipt of fg"
Step 3: mungoflago goes to send paparick any amount of fg and is prompted to use temp password, types it in, password automatically gets reset to my old password"
Step 4: confirmation email gets sent to mungoflagos email saying his fg has been successfully redeemed
OR
This is under the assumption that people don't typically scam within a finite period of time (unclear if this is valid or not:
Step 1: mungoflago buys 100 fg via paypal
Step 2: mungoflago receives a confirmation email stating "thanks for purchasing fg. you MUST reply to this email within 10 minutes or your fg will be locked until you do so"
Step 3: mungoflago logs into d2jsp and sees +100fg in his bank
Step 4: mungoflago replies "confirmed" or some variation of a set standard word that's easily interpreted by by an automatic email reader linked behind the scenes to jsp's programming
Step 5: mungoflago's fg doesn't get locked