So, unlike me, I read the smallprint.
In short it allows them to take from my paypal account for this transaction AND future transactions for any amount !!!
As this was a one time purchase I was none too happy with that so had a look at my paypal account to see I have another billing account that was active with Stubhub. In effect it appears they could take any amount at any time from my account also.
Not sure I am comfortable with that so into my account, settings, payment settings, pre-approved payments, select the merchant and change status to inactive