ive beentold by a few different check in staff at different SPG hotels they they must manually check the box or whatever at checkin to send an email (otherwise it defaults to sending nothing). Not sure how true that is as there are some hotels where I’ve never not gotten a receipt after nightly audits and then again when I’m finally checked out late morning/afternoon but there are some where I’ve never gotten emailed a receipt, even days later and making a point to ask at checkin. I miss the days of them sliding one under the door (a few random locations still do this). I make it a point to grab a hard copy when leaving if I don’t already have one in my inbox but it seems like every time I’m in a rush and don’t get one is when I’ve gotta email their back office but sometimes that takes a week.