When I looked at the data I was slightly surprised by the variation in the ratio of yellow cards to fouls. The table below shows a large variation in the number of fouls that became yellow cards. Cork's 75% in the All-Ireland quarter final is at one end while Kilkenny's 0% for 12 fouls in the Leinster final is at the other end.
There are some serious data limitations. First, the numbers for "fouls" only quantify the times the referee blew the whistle. Occasionally, the referee will allow the play to continue and issue a yellow card later. This occurred in the Galway-Cork game when Cyril Donnellan (Galway) was shown a yellow cards for a late tackle on Aidan Walsh. Second, there are only five games in the sample below. Many more games would be require to draw an definitive conclusions.
Allowing for these major data limitations, two points might be made. First, the two Leinster games had 49 fouls and 4 yellow cards while the two Munster games had 37 fouls and 12 yellow cards. Would there be a difference between Munster and Leinster games if we had a larger data set? Second, the two games with the highest ratios of yellow cards to fouls were refereed by James Owens. This is not to question his handling of the game. Moreover, ex-intercounty John Bannon has suggested, in an Irish Examiner article, that the referring display by James Owens was such that it might earn him the ultimate honour - being asked to referee the All-Ireland final. However, Owens' ratio is much higher than James McGrath who refereed the Dublin-Galway and Kilkenny-Galway games below. Again, it would be useful to see more data.