Why do threads like this always pop up after each home game? No offence to the OP.
At the end of the day, whether people like to admit it or not, the stadium was near enough full. Some people might point to empty seats, and that shows the stadium isn't full, but there were hardly swathes of empty seats visible. More like pockets in certain sections of the stadium.
As some people have rightly pointed out, it's the Easter Weekend when many people go away for a holiday or break. When I checked on Viagogo on Friday there were roughly 150 seats for sale, and a large amount were from private sellers who for whatever reasons couldn't attend the match, even though they had paid their money upfront. (I noted with interest the empty seats at Arsenal yesterday, especially in the 2nd tier club level)
What the OP forgot to mention was the home fans in the upper tier of the away end.(see the picture below which I've already posted) It was completely sold out. That's an extra 1000+ City fans that wouldn't have got a ticket if Newcastle United had taken their full allocation.
Put it this way. If Newcastle United had taken their full allocation, and City would have been able to accommodate those extra 1000+ City fans sat in the top tier of the away end, the attendence for yesterday's match would have closer to 50,000.
Click to enlarge. Note the upper tier away end full of City fans, and the pockets of empty seats around the stadium. Mostly visible in the Family Stand.
[bigimg]http://i.imgur.com/LfSGjfs.jpg[/bigimg]
And yes, there were Tourists there yesterday. Think they were Spanish? Suitably dressed for our cold, but recently dry climate. There were also tourist from the Far East, etc.
Don't think she was too impressed with me taking a picture. :-)
[bigimg]http://img507.imageshack.us/img507/7263/20130330154956.jpg[/bigimg]