Were you asked for a captcha code? For some features, YouTube will ask for this to make sure you are a real person. As far as getting banned:

We have thousands of customers using our product, some of which have been using the product for the entire 4 years we have been in business. Using our product as designed will not get you banned by YouTube. The default settings are configured to follow YouTube’s terms of service.

However, we have had customers in the past who have been banned by YouTube. Those accounts either did not follow our guidelines/default settings, did not target their audience, or sent messages that were “spammy” in content. This link contains information on how to target your audience and use Tube Toolbox to its fullest - http://www.tubetoolbox.com/Guide.aspx.

All that being said, some people create a separate account to use for marketing through Tube Toolbox. They use this account to send messages and reference their primary account. This provides additional protection in that if their new Tube Toolbox marketing account is cancelled it will not impact their primary account.