I'm not affiliated with PB, but I was interested in seeing what your reaction was about, so I took a look at the LL34 league.

Actually, every offensive player on Amboy is rusty, and almost all of Baltimore's offense is too. Like Brown did for Baltmore, Clemens pitched the Amboy 4th game, and he is also listed as 5 days rest, as are the relievers used in that game after him.

I think the explanation is a bit less "grassy knoll" than you think.
It appears as though PB is treating the unplayed games 5, 6, & 7 as "days off". As per the playoff rules stated in the manual, you now add the the scheduled "day off" between games 5 & 6 and the scheduled "day off" between series', and you now have 5 days of rest for the pitchers in Game #4 of the previous series.

It looks to me like both teams are being treated the same way. The offensive players for Baltimore that aren't listed as rusty are Utility and Part-Timers, and per the rules, they have a longer period of time before they get rusty.

I certainly do think that PB has some bugs that need to be worked out (non-catchers throwing out lots of basestealers and SP/RP's maybe coming back too easily after starts are 2 of the more common complaints), but I really don't see "cheating" as being one of the problems.

Heck, I was in LL17 and the owner of the St. Louis Browns was one Michael Bravard.

The Browns were swept in the first round of the playoffs.