When companies poll between elections it is reasonable to ask about support for all the serious political parties, but when it comes to during election pollsters have to ask more detailed questions, spefifically they have to ask about the actual candidates on the ballot.
One nice thing about using online panels is that as a surveying method it is very, very easy to make sure that people get questions that have the actual candidates they can vote for. The company has the address of all their panelists so knows which riding they are in. They also know who all the candidates are and can very easily customize the survey to each riding. I can not imagine any serious pollster with any understanding of statistics not doing this especially if they are using online panels.
Can you imagine a company being to lazy to ask the right questions and then still publishing their results? With the ability to so easily ask the right names for each riding no one could possibly be stupid enough to ask people about parties they can not vote for.
So why is this so relevant in this election? Because the Greens and Conservatives are not running full slates. The Greens have 61 candidates and the BC Conservatives have 56 or 60 - 4 BC Conservative candidates are on the ballot without the party name. The province wide numbers for the Greens and the BC Conservatives will look lower because they are not running full slates. I means their support levels are higher in the ridings where they are running candidates than the average.
In the case of the Greens on Vancouver Island, the party is running 11 candidates in the 14 ridings and getting results in the 20% range for the whole island. But since in three ridings there are no Greens, the real level of support on the rest of the island is closer to 25%.
So to read the polling numbers of the Greens and Conservatives more closely to what they would be if they ran full slates, you need to account for the ridings they are not running in.