I ran into a little trouble 4 years ago. I was rejected for a mortgage based on some qualities of the Condo, not my finances. Anyway, in the aftermath, I gave up. Then I found travel hacking, and we added 3 cards for me and 3 cards for my my wife. Then a more expensive townhouse came along, and we applied for a loan with a different mortgage company. Apparently, some of the banks were scrambling account numbers that they reported to the credit bureaus to protect privacy? The mortgage company was concerned with the massive new credit lines that were opened, even though they all had zero balance. (I had already cleared the bonuses.) They kept trying to match the accounts with the cards I told them I had opened, and they all had the same application date, so we could not determine which account was which.
Eventually, I wrote a letter to the bank and randomly matched the accounts. I could have been correct? I explained I had no intention in using my credit, and explained that we had opened the 6 accounts to earn 250,000 travel points. The tone of the letter was kind of frustrated and annoyed. After sending it, I thought I might have made a mistake. Shortly after the letter was sent, they approved the loan on my vacation home in Myrtle Beach. The loan went through. Loan application to closing took about 45 days.