To my knowledge the YouTube API doesn't ban users for excessive use of the API, it just throttles them temporarily.
The exact throttling values are not posted publicly, but there are multiple third-party apps using the YouTube APIs successfully, so I expect the limits are high enough for a standard client to work without problems.
The exact throttling values are not posted publicly, but there are multiple third-party apps using the YouTube APIs successfully, so I expect the limits are high enough for a standard client to work without problems.