This is what I (as a TD) always do with house players, particularly when the house player has a relatively high rating. I once had the misfortune to be the odd man out in the last round of a 4-round tournament in which I had gone 0-3 in the first three rounds. So they gave me the option of playing a 2100-rated “house player”. Why would I want to do that? The whole methodology of the Swiss system is geared toward progressively more competitive pairings, so that if you’re overmatched in general, you get someone closer to your own strength in the later rounds. If I can’t make any progress vs. Class B players, why would I want to play an Expert? The method Alex describes gives the odd man the same general level of pairing he would expect to get with an even number of players, and that seems desirable to me.