Antonyms for the phrase "are surety for" could include phrases like "are not responsible for," "do not vouch for," "are not accountable for," "are not answerable for," or "are not liable for." Each of these phrases suggests that someone does not take on the responsibility or obligation of ensuring or guaranteeing something else. Instead, they may distance themselves from the matter or refrain from making any promises or commitments. These antonyms highlight the opposite end of the spectrum from being a surety, which involves assuming legal or financial obligations on behalf of someone else.