An interesting article in The Guardian looks at the question of attendance figures. It points out that these are never just a dry statto matter, but that football fans get quite emotional about them: Attendances
The article argues that attendances have long been inflated in the United States because they help to attract commercial sponsors or avoid the loss of a franchise. This practice has spread to the UK, in part because of American investors in football.
In the past attendances often understated the crowd. First, some clubs creamed off some of the gate money so they would not have pay 'entertainment' tax on it. In the days when the away team got a share of the proceeds, this would mean less money for them. (The newspapers used to publish gate receipts as well as attendances, but the figures were not reliable). Second, gatemen had various fiddles such as letting pals in at half price and pocketing the money. Third, at most grounds, certainly at Charlton, there were ways for youngsters to get in without paying. Some of the really big Valley attendance figures may understate the size of the crowd.
One complaint against the current regime is that they have inflated attendance figures. Clubs do have to count season ticket holders whether they are there or not because of the levy they pay on attendance to the Football League.
However, it does seem that the current regime has been generous in giving away complimentary tickets. Some have to be provided: for example, the referee is entitled to some for his mum or those who like to follow their favourite man in black. Of course, giving away tickets to schools etc. can be a perfectly sensible marketing strategy. But it does mean that the attendance figures do not offer a reliable basis for comparison across seasons or matches.