The convention tickets are not just meant for the actual people who attend conventions... they are meant for the family members as well. You are allowed to purchase up to 8 tickets per single convention attendee. They DO expect people to take advantage of a business trip to attend a convention and combine it with a pleasure trip to visit Disneyland. They DO expect people to physically be in Disneyland in days both Before and After the actual convention dates. There is a specific time frame, I believe 3 days after the end date of the convention, that the DL convention tickets use as an expiration date but I have no idea if they check or enforce that.
I highly doubt that Disney corporate finds broadly defined use of convention tickets a problem on the same level of a problem as ticket brokers. Ticket brokers are taking money directly out of Disney's pockets by taking business of people who would otherwise be buying tickets directly from Disney. Convention tickets are still official channels of purchasing tickets - Disney is still pocketing the full amount of money that they wish to make from convention ticket sales even if it is less than a full price ticket. It is all about their different channels of marketing. They are trying to bring in business of people who are already coming into the area who might not care about going to DL but enticing them to visit the parks and hey, bring your family, too! with an incentive of a slightly cheaper ticket price than they can get through traditional channels like AAA or Costco tickets.
Here's the official info site for Disneyland Convention Tickets but they have not updated the info for 2013 and the info listed is for tickets that expire in 2012. I presume that the ticket prices have increased but the general fine print info is the same.
http://www.disneyconventiontickets.com/disneyland/parks/tickets/