Is it illegal to print ads on cups?

Not illegal, they fooled around! Now in order to maintain their old customers, develop new customers, will be appropriate to do some advertising gifts - that is, in the cups, umbrellas, mouse pads and other gifts on their own company logo as a publicity. Give back to customers. But these gifts are not their own company, but as some promotional tools. For example, mobile, Unicom have gifts with the business, banks also have points gifts, do these companies have the right to produce gifts? Another example is the bus advertisement, does the advertiser have the right to produce buses? Purely irrelevant things, nonsense! We are specializing in gift companies, to break the law where we survive ah?