Things can, however, go wrong. Sometimes the loan that was supposedly approved wasn't, because the lender comes in with terms with which the purchaser cannot comply. Buyers have been known to show up at closing anyway, in the hope that the seller will reduce the price in order to close. On the other hand, it may well not. Another possible snafu is that the title information comes back and reveals that the house has a lien against it that no one knew about.
Most states now require photo identification at the time of settlement from all parties involved.
A husband and wife may show up having been married for two days, and the credit check on the woman may show that she has eight aliases and is wanted in Montana for sheep rustling. In this case, the loan will have been turned down. These scenarios, while they do exist, are not likely. However, be sure to take the responsibility to examine the paperwork and examine it well. Ask whomever is handling the closing to explain it to you.