I have an Eventbrite event and PayPal payment method. Some clients (and myself on one of my computers) have trouble: when they want to pay by card on Eventbrite and they click the Mastercard or VISA icon, they are redirected to PayPal page which requires login, instead of to PayPal guest checkout which allows direct card payment. Normally the guest checkout works, but sometimes (possibly for users that have been logged to PayPal previously) this problem occurs.
I found a workaround, that if I open the Eventbrite page in browser Private window, which removes any cookie and history context, it works and suddenly PayPal guest checkout works. But this is not the solution for the clients.
I followed these instructions to allow PayPal guest checkout to set in my PayPal business account (the one linked to the Eventbrite page, i.e., the one which collects money from the tickets) the option "PayPal account optional" to "On", but it was already enabled and still this problem occurred.