Is the Wallet supply limited to 56 only?
I ran out of Wallet tokens very quickly in a 5-player game last week:
Initial setup: 36 tiles + 4 more for each corner tile = 40 Wallets
Someone stole from a marked Farmer and used "Money Tree":
"Place one Wallet from Lost & Found on the Farmer and on each Guest tile that surrounds her." = 9 Wallets
Then someone stole from a marked Paramedic and used "Stretcher":
"Choose a row or column. Add 1 Wallet from the Lost & Found to each Guest tile in that row or column." = 6 Wallets
40 + 9 + 6 = 55, there's only 1 Wallet left in L&F.
When I correctly exposed a player next turn, I could not get enough reward Wallets (2) from L&F.
Wallets are an unlimited resource. If you happen to run out, you can use something else like counters, coins, or other tokens.
The situation you described is extremely rare, so you probably won't run out of Wallets again, but if you do, you can use something else to represent them as needed.
Hope that helps!