There are no known issues any of these two sites. B2B will help when it comes to working with business 2 business since you are working with the owners instead of the companies.
There are many laws to protect customers and the general public. Websites with ethical issues involving the general consumer could mean more serious or damatory consequences than business to business.
There are no real ethical issues, that are not common among the companies, only if a B2B site have there own requirement which if another companies does this then there may be an ethic issues.
