Are your clients a corporation?  "All corporations incorporated in the State of Delaware are required to file an Annual Report and to pay a franchise tax....  For an Annual Report or Amended Annual Report for non-exempt domestic corporations the filing fee is $50. Taxes and Annual Reports are to be received no later than March 1st of each year. The minimum tax is $175.00 with a maximum tax of $200,000.00."

https://corp.delaware.gov/howtoform/ 

My guess is that someone went to a seminar where someone told them that a Delaware corporation is a status symbol that will help them get dates.  But I could be wrong.