I have a 3 night reservation in early June in Lisbon at Shiadu hotel (this is the brand/company, I suppose). I reserved it online. No credit card was required. I emailed to confirm that they didn't need a credit card to hold the reservation and they said no -- pay on arrival. Is this common? I gather this is a busy time of year in Lisbon and I do NOT want to show up and have no room. Thanks!