If I'm going to cover a game, I've got my computer bag with me, so that's where my notebooks and anything else goes. A suit coat with stuff in its pockets just looks sloppy.
At the local U, the PR folks wear khakis and matching polos to football games, and suits and ties (for the dudes; similar attire for the ladies) to basketball games.
If it's just an iPhone and a pen/pencil and a reporters' notebook, or a little Muji A6 or something, it shouldn't ruin the line of your suit too much. Depends on the cut and the tailoring. Frank Ridgeway and I would both favor a classic sack-suit cut for that very reason. Depends too on the nature of the work you're doing.
Think all pro sports, except baseball or football in some Sept games, team PR guys are wearing suits.
There's a terrific debate we have about your last line. I used to think the way you do about travel dress. Now, I think airlines/hotels only care if you have elite membership in their reward plans. Great thread. Lots of good points.
It's correct to say a suit carries less weight than it used to when trying to snag an airline upgrade or sweet talk your way into the Admiral's Club or leverage a better hotel room or a nicer table in a restaurant. Points programs undid most of that. But the impression a suit makes can still have its advantages in those business travel settings. And elsewhere. And traveling in the suit also saves space in your suitcase. I can wear one, pack two, and cover a ten-day road trip with a 21" carry on.