From what I recall, some temples / priests / elders keep a record of this within a community. And yeah, that is one of the reasons why marrying outside your com

From what I recall, some temples / priests / elders keep a record of this within a community. And yeah, that is one of the reasons why marrying outside your community, with or without your parent's consent, is such a big deal in India (not just with the Hindus who subscribe to gotras but also among other communities, as the emphasis on arranged marriages are often on "shared values" between the families. It's harder to determine what values an "outsider" or their family has, as it becomes harder to use your social circles to investigate them. )