There isn't as big an away culture in Spanish football, and I don't think it is as uncommon to see away shirts in the home ends as it is here. I think at the El Classico, for example, you get get a lot of tourists wearing Barcelona shirts in the Bernabeu and as long as you are mostly respectful they don't mind as much if you celebrate.Genuine question. Are away supporters officially allowed in home ends? Two guys in front of me in the security queue last night were speaking in Spanish and wearing RM caps, shirts and scarves. A couple of stewards came over and told them to remove their caps and scarves. When they queried why, they were told it was a home end and it was for their own safety. They argued for a bit, took them off while they were scanned and then put them back on before they went through the turnstile watched by the stewards. I later saw them being escorted out after celebrating Madrid's first goal. Now I've sat on my hands many a time in 'wrong' ends, but If I'd have turned up in full colours I wouldn't have expected to be let in.
And I haven't worked security, but I get the impression that you don't want to kick people out unless you have to because it has more potential to kick off than if you just ask them to follow the rules.