It’s a matter of what works for the site/organiser and for the player base.
Taking a deposit places value in the booking for the customer, makes it more likely for them to turn up as opposed to deciding their duvet is warmer than going outside, and if they don’t turn up its a contribution to the cost of paying the marshalls that you have being very underworked.
But there are people who won’t want to part with cash in advance .... because it’s not pay day yet, they want the fraction of a penny interest, or they know that they are the type of player who will decide not to turn up and lose their deposit
For the site the number of players expected may or may not make a difference. They could run with a set number of staff anyway, or they may be able to cater for various numbers of players and increase the marshalls to maintain a safe player/Marshall ratio. (That also relates to the type of player and balance between regular players and inexperienced rental players)
There is a minimum safe ratio of Marshall/player and the maximum capacity of the site
If you have staff on site with no customers then you are wasting wages without income. A site probably has a mixture of ‘full time’ staff and part time / zero hours contracted staff.
If staff are on contracts with a guaranteed number of hours working then they know how much they will be paid, so staff are willing to work for you and it doesn’t matter if no players turn up as you have the overhead cost anyway.
If staff are on zero hour contracts then their income is unreliable as you don’t put them on shift unless you have enough players. You then end up paying them to do nothing or don’t call them in for work. They will end up leaving for a job that will enable them to pay their bills