Originally Posted by
joshwex90
I though Diners only issued Diners

Diners Club does not issue cards. Diners Club International licenses banks to issue cards in a specified geographic area. For the past three decades this has not been apparent because Citibank owned both Diners Club International -and- was the card issuing franchisee in many areas.
In 2005 Citi converted the Canadian and USA franchises from the Diners Club network to MasterCard network. Later, Citi sold Diners Club International (the network operator) to Discover, and they sold the Canadian and USA card issuing franchises to the Bank of Montreal (BMO) which owns Harris Bank.
Originally Posted by
G2244
Is there a history of DC offering sign up bonuses?
There is no relevant history. It has not been possible to apply for a USA (or Canadian) Professional (personal) card account since 2008. Citi stopped issuing new accounts several years before selling the franchise to BMO in 2010, and this is the first time that BMO/Harris Bank has accepted applications. Does Harris Bank offer new account bonuses on other cards?