Referral Etiquette in MBB Recruiting

For recruiting for entry-level roles (internships and full-time positions straight out of undergrad) at MBB US offices, would you advise explicitly asking for referrals from people you coffee chat with?

Some people say referrals can meaningfully help and that it's a missed opportunity not to ask after building rapport, while others suggest that strong advocates will usually offer on their own and that directly asking can come across as transactional.

For those who have recruited for or worked at MBB, what's the norm? If you think it's appropriate to ask, at what point in the relationship/conversation would you do so?