Well... Banksias grow in fire prone health lands, and the seed heads need fire to open up. I put them in the oven for about 20 minutes, but I know people who burn them in a small fire or even use a blowtorch.
There is some research that indicates certain plants germinate better after smoke treatment. But its a bit of a unknown thing at the moment.
There are a number of pre treatments for growing things by seed. Scarification of Grevillia, where you use a bit of wet and dry to slightly scar the seed, I have done that before. Some North Queensland species need the to go through a gut of a Cassowary to germinate, so people use Coca Cola to imitate that. There really is a number of ways that help certain plants, they are usually kept secret by growers, but I say.. Spread the love :D