They said they polled 120K people on their website to gauge the sentiment for this idea. Isn't it true that polls that depend on self-selection are very biased?

They said they polled 120K people on their website to gauge the sentiment for this idea. Isn't it true that polls that depend on self-selection are very biased? That obviously doesn't completely invalidate the idea, but isn't it a bit much to use it as supporting evidence? The answer was an overwhelming 'yes' if the tickets were free. Two-thirds of respondents said they’d stand on flights of less than an hour if their tickets were free; 42% were willing to do so for tickets that were half-off. In this case, who knows, it may be only that the hardcore, frequent fliers responded to the poll and that the majority of fliers actually hate the idea.