ColchesterFC
Journeyman Pro
Would 4 balls make it a lot longer? Probably adding about another 65 to 75 shots in each group. Maybe longer than they want. And they'd have even more golf to try and cram in to show the viewers, or just decide to ignore more golfers entirely.
I read on the BBC Sport website that it took 4 hours 45 minutes for them to get round as three balls yesterday. I can only imagine that if you made it four balls you'd quite easily be pushing six hours to get round.