Yes, they are playing the course under the same rules. I don't have any problem with the rules of THAT game but it's not the same game as disc golf. Players expect to get ratings and I'm not sure you can combine results from this USDGC game and what we have been rating. It's like combining basketball scoring stats from before the 3-pt shot was created versus after. It's pretty much the same game but would you consider it fair to combine stats and compare players' shooting stats and skills before versus after?
Ratings are based on your play at that event with those rules against those competitors. The ratings would hold up, in wind, rain, snow, OB lines, Stroke and distance, because all players are playing the same rules. The ratings right now are about right and will average out after 4 rounds. The best players will be about where their ratings are on average. I think your arguement would only be valid if the OB rules were removed halfway through a round.
Ratings aren't effected by the course or rules, much. Just score to par.