They do, candidates have to explicitly endorse all campaign ads, there’s no requirement on placement really, I’ve heard a few ads where it was done in the beginning as part of a “ad read”

It was something like “I’m (candidate) and I approve this message because people need (cause here)”

From wiki:

The "Stand By Your Ad" provision (SBYA) of the Bipartisan Campaign Reform Act (BCRA, also known as McCain–Feingold Act), enacted in 2002, requires candidates in the United States for federal political office, as well as interest groups and political parties supporting or opposing a candidate, to include in political advertisements on television and radio "a statement by the candidate that identifies the candidate and states that the candidate has approved the communication".

The provision was intended to force political candidates running any campaign for office in the United States to associate themselves with their television and radio advertising, thereby discouraging them from making controversial claims or attack ads.[1]

In American politics, "I approve this message" (sometimes in the past tense, also with "authorize" in place of "approve" or with "ad" instead of "message") is a phrase said by candidates for federal office to comply with this provision.

They do, candidates have to explicitly endorse all campaign ads

From wiki:

The "Stand By Your Ad" provision (SBYA) of the Bipartisan Campaign Reform Act (BCRA, also known as McCain–Feingold Act), enacted in 2002, requires candidates in the United States for federal political office, as well as interest groups and political parties supporting or opposing a candidate, to include in political advertisements on television and radio "a statement by the candidate that identifies the candidate and states that the candidate has approved the communication".

The provision was intended to force political candidates running any campaign for office in the United States to associate themselves with their television and radio advertising, thereby discouraging them from making controversial claims or attack ads.[1]

In American politics, "I approve this message" (sometimes in the past tense, also with "authorize" in place of "approve" or with "ad" instead of "message") is a phrase said by candidates for federal office to comply with this provision.