A recent decision of the UK IPO demonstrates the importance of filing evidence of reputation, if available, as well as sufficient evidence of use when an opposition relies on a mark which has been registered for more than 5 years.
HBO hit a stone wall enforcing their GAME OF THRONES trade mark against a UK brewery. The reputation that HBO enjoy in their Game of Thrones television show has encouraged other traders to take a nod to its title in their own branding. While HBO have often taken steps to address this, they have not always been successful.
Infringement case involving the trade mark BUTLERS IN THE BUFF.
It is not unusual for a company to rebrand. The intention may be to attract a new target market for a product or to maintain the interest of existing customers.