No it isn't - it's a way of deterring time wasters.
Taking a reasonable sum off new members and charging them a monthly subscription also encourages them to take advantage of the low rental costs which can then be offered. Total cost to them actually breaks even if they do 6 hours per year compared with costs incurred at places where the subscriptions are lower, but the rental costs higher.
'Flying schools' don't have many rich owners or shareholders, of that you can be sure!