As of September 2013, the SEC requires companies that publicly discuss their financing to take steps to verify that investors are accredited. This means you must provide evidence of your accreditation when investing in 506(c) funds, which are funds that publicly market that they are raising money, like AngelList Access Fund and most of the Rolling Funds. This involves providing documentation that shows you meet one of the accredited investor thresholds.
Funds that do not publicly discuss their financing do not require evidence of accreditation– the investor may simply state they are accredited. This applies to most syndicates and funds on the platform, where access is invite-only.