You might lose a game on time because your move took 3 seconds to register.
A: Generally, no. They care more about engine cheating than network routing. However, if you share a proxy IP with a cheater, you might get caught in a collateral ban.
Leo’s hands went cold. He looked back at the proxy site. It wasn’t a tunnel. It was a net. Every move he’d made, every keystroke he’d typed while logged in, every browser cookie—they’d harvested it all. The “proxy” was a trojan horse, and he’d wheeled it right into the castle.
While the desire to play chess is strong, you must be aware of the dangers of free proxy sites.
If the stealth URLs above are also blocked, general web proxies can act as intermediaries to load the site. JSM Central
A completely free, open-source alternative. Many school filters block "Chess.com" by name but haven't caught onto Lichess yet.