From what's happening these days and what I see, it looks like the marriage expenses are picked up who is the aspirational partner in the relationship. In my community the bride's family too up the expenditure in the past.
If the groom is tier 1 , and the brides family approached them for marriage,then the bride's family picks up the tab. If the bride is teir 1, and the groom family approached them. Then equality steps in and the groom's family voluntarily takes up half of the expense or does the marriage reception separately so the bride's family doesn't need to do it.