I don't think us offering a discount for Dabbers fans to come and watch The Alex is gonna generate much in the way of extra revenue.
Infact it's probably more likely to lead to less revenue for CAFC as the few Dabbers fans that also watch Crewe would probably have paid full price anyway.
In short there just aren't enough Nantwich fans full stop to make it a goer of an idea.
Reverse the roles though and Nantwich would be more likely to benefit in allowing Alex fans in at a reduced rate.