Back when I was working at a (Australian) TV station, when we covered baseball we had a radio mic on the home plate umpire...as well as a lipstick camera in his hat. Because the league was trying to expand its fanbase, they allowed the umpires to be wired up in this way. The umpires were all in favour of it too...
So that mic got us the ball/bat/mitt sound, as well as the umpire's calls...and the heated arguments. Unsurprisingly, it was this that caused the biggest gaffe* to go to air...so much so that it made the Xmas Tape Blooper Reel of every network in the country.
We had "disposable" radio shack lav mics hardwired to 1st and 3rd bases for the ball in glove/foot on bag sound. 2nd base was covered by a Sennheiser 816 from near the home dugout.
Cheers,
Tim
* For those interested in the actual incident... Batter at the plate, has received a number of pitches. Scoreboard not keeping up, so he asks the ump what the count is. Ump isn't sure (!!!) so he asks the ump at 1st...who shrugged his shoulders. Commentators have said "let's listen in.." and then stopped yakking. Director says "pump the audio"...and the ump says (rude word alert) "No cunt's got a counter!" That hit the meters at about +3. Cue stunned silence from commentators and director. Audio director, 2nd AD, and all the AA's all proceed to piss ourselves laughing.