Unless those markets are checked by U.S. regulators. The Commodity Futures Trading Commission (CFTC) has oversight on prediction markets like Kalshi and PredictIt. On December 13, all wagers related to Magione vanished from the sites. According to Bloomberg, Kalshi removed the Mangione-related wagers from its sites after it received a “notice from…regulators.” The outlet writes that the CFTC “bans futures trading linked to crimes including assassination, terrorism, and war if the agency decides the so-called events contracts are against the public interest.”
On Polymarket all assassin-related bets are on. “Will Luigi Mangione fire his lawyer before 2025?” Polymarket has the odds at just 1 percent. “Will it be confirmed that Luigi Mangione used psychedelics?” The users give it a 43 percent chance. “Luigi Mangione motivated by denied claims?” On December 10, Polymarket had this at a 75 percent chance, but it plummeted to around 25 percent.
It’s a lot harder to shut down dark web sites, like the Silk Road that ran for years. Both the website and the payments need to be difficult to shut down.
On dark web sites you generally deposit to an account, so you’d only pay the Bitcoin transaction fee for deposits and withdrawals. As of this writing that’s under a dollar, for any number of bets.
If you want to use a bunch of different dark web sites, and/or want improved privacy, then you can use the Lightning network, which has onion routing like Tor and drastically lower fees. Or just use Monero; my point isn’t really specific to Bitcoin.