On Friday, BBC Radio 5 Live's phone-in discussed the cost of policing the Royal Wedding.
Reality Check had already looked into the question of how much the taxpayer could be contributing to this.
Jill, the first caller, said that public money should be paying for policing at the wedding because we also pay for police at events such as football matches, film stars' weddings and film premieres. So, is Jill right?
The policing of football matches is almost entirely publicly funded.
In 2012, Leeds United won a High Court action against West Yorkshire Police, with the judge ruling that the club only had to pay for police inside the ground and on land that it owned or controlled.
Andrew Dismore, a Labour member of the London Assembly, has been campaigning for clubs to contribute more towards the policing around their matches, and asked the Mayor of London how much this policing had cost in the top two divisions last season.
The most expensive club to police last season was Tottenham Hotspur, which was playing at Wembley while its new stadium was being built. That cost £1.2m, with only £62,000 being recovered from the club.
Police forces generally have to meet these costs out of their existing budgets, but when they have to put significant resources into big events or operations they can apply for extra funding from the Home Office.
A force would have to be spending more than 1% of its annual budget to be able to apply for extra money. Given that the Metropolitan Police's annual budget is more than £3bn, football matches fall a long way short of making up 1%.
The most recent available grant applications are for 2016-17. South Wales Police was allocated an extra £1.4m for policing the Champions League Final between Juventus and Real Madrid in Cardiff (it had bid for £3m).
Also that year, Merseyside and West Midlands Police were granted extra money for securing the Labour Party (£364,191) and Conservative Party (£2,217,343) conferences, with additional grants for the Office for Security and Counter-Terrorism (OSCT).
The previous year, South Yorkshire Police was given an extra £148,358 towards the cost of policing English Defence League (EDL) demonstrations.
The tricky bit when thinking about the cost of securing a big event is deciding how much of the cost is in addition to what would have been spent normally.
For example, you would expect there to have been some police on duty in Windsor on Friday anyway - should Thames Valley Police count them as part of the cost of policing the Royal Wedding or not?
When the force is having to pay overtime for extra shifts or buy in special equipment, that clearly counts as an additional cost. But if you have officers who would have been on duty in a different part of a city, or even in a different city, should you consider that as an extra expense?
That is the question with some of Jill's other suggestions. For film premieres, the Metropolitan Police told Reality Check: "Policing in central London is geared up for dealing with big events."
You would usually expect there to be police in Leicester Square, where many premieres take place, so the extra cost would be minimal. If anything, it would mean that there might be fewer police on duty in other parts of central London, but it is hard to put a cost to that.
So while strictly speaking taxpayers are paying to have police there as opposed to anywhere else, they are not paying any more than they would have done if there had not been a premiere.
Venues staging film premieres would usually lay on their own security, but they could hire additional police officers if necessary.
The same is true of concerts at big venues - the police consider it to be part of their usual activities so there is no additional cost to the taxpayer.
The Reality Check team has been unable to find evidence of a film star's wedding in the UK requiring extra policing, but a freedom of information request lodged by the Mirror found that 35 officers had been employed at the 2011 wedding of the model Kate Moss.
Gloucester Police stressed that the costs would be met in full by the event's organisers.