That would be a different test, methinks?

You're assuming that the taste is only affected by what it's being served in, not how the liquid was transported. For all we know, aluminum imparts some sort of off-flavor into the Coke itself that the OP doesn't like, in which case it wouldn't matter if he decants it into a glass first--it would already have been "tainted" by being held in the aluminum can.

It may again be placebo effect, but I can still taste the difference in bottled water poured into my steel water bottle and my usual filtered tap water.

I also can't stand plastic bottled sodas, and can tell they've been sitting in one even if drank out of something else after opening.

I fear the bottling/canning process and length of time spent in it gives it a bit of a whiskey-barrel style finishing taste alteration.