Interesting article. This is exactly what many Paypal users will want to do with their Bitcoin fun tokens. Not as if you can do much else with it anyway. If this is an issue Paypal should be upfront and very loud about limiting personal trading on there. They should have been fully expecting it.
The sad thing about all of this is that the people (more than likely) that are going to be using Paypal as an exchange will be people that are brand new to the industry. This is going to lead towards a bad sentiment for BTC overall and it is going to have absolutely nothing to do with BTC, but rather paypal's setup and inadequate policies. This is just a shit show waiting to happen, I just feel bad for people. This whole realm is complicated enough without having Paypal or some other company either acting like an exchange or getting into a space they are not prepared to enter.