It seems like this should be common sense, but apparently it isn't... so I'll state it as clearly as I can:

You have no right and really no reason to go through another team's packet without that team being present... period.

This especially applies after the match because there's money in there - or it could be that you're trying to cheat (change score, change innings) or just being nosy/paranoid about YOUR behavior during the match (did they mark us down on sportsmanship or write a note?).

If you're worried about a note or a sportsmanship rating, then you probably feel guilty about something you did during the match... and shouldn't have done it in the first place.

You get your chance to check and validate the other team's scoresheet at the end of the match when you sign their scoresheet and they sign yours. Heck, take a picture of it at that point if you really want to. After that, hands off. If you realize later that there might be a problem with their scoresheet, contact the team captain for that team or bring it to my attention.

I take this seriously for good reason (which should now be apparent with what I stated above). This is the type of thing that can earn you a suspension or permanent ban from the league, depending upon specific circumstances.