Ontario kitchen reno: does a gas range require a 240V 50A receptacle?
UPDATE: @doozit commented below that this document was just a proposal, which wasn't accepted. (It isn't described as such on the ESA webpage) 

A quick google search found what looks like the answer in the Ontario amendments to the Canadian electrical code on the Electrical Safety Authority's page

This reference might be enough for you and your electricians to break the tie:


  31.Delete CE Code Rule 26-744(4) and replace with the following:
  
  (4) A receptacle of CSA Configuration 14-50R, as shown in Diagram 1, shall be
  installed at a suitable location in every single dwelling and in every dwelling unit of an apartment or similar multi-dwelling building for supplying electric energy to an electric range.
  
  32.Add Rules 26-744(10), (11), (12) and (13) as follows:
  
  ...
  
  (13) Notwithstanding Subrule (4), the range receptacle need not be installed in
  
  (a) dwelling units where a built-in gas-fired or electric cook top or a built-in gas-fired or electric oven is installed;
  
  (b) other than single dwellings where provision has been made for a gas range; or
  
  (c) dwelling units where power from a supply authority is not available and the capacity of local generation is less than 6 kW.


So it looks like you don't need the receptacle as long as a cooktop or oven is installed.