Once the Ethereum Mainnet transaction is sent, NiceStars honors the quoted ETH rate even if the market shifts before confirmation lands.
A card buyer never sees an exchange rate at all — the price is just the price. Someone paying with ETH sees the rate explicitly before committing.
A browser tab left open too long can show an outdated ETH rate — refresh the page before paying to be sure.
The quote refreshes every time the Stars amount changes, right up until payment is sent.
Yes — once the Ethereum Mainnet transaction is sent, that quote is honored regardless of market movement afterward.