Do you think you'd ever make a card with a double divinding line? Or if you can't answer that, would a doube line ever stop a card from existing? Or at least be a significant point against it?
HiG put a double dividing line on the German Lighthouse.
I decided against doing it because it would be extra complex. It's killed concept arrangements in the past; I don't have an example offhand, but like, if Highway had wanted a when-gain ability, I would have done Highway differently, or put the when-gain elsewhere, you know. None of the ideas necessarily die, but the combination does.
There are cases where a card is cheaty on the dividing line; Noble Brigand says "when you buy this or play it," which are two different times but there's no line. So that's a way three timings could sneak onto a card.