I'm too lazy to read what everyone is saying, but foliar feeding of Nepenthes is more or less a waste of time. Seriously, the benefit is so low that it isn't even worth the time spent mixing it up and spraying down the plant. Try the pitchers or media to get a real benefit. The best Nepenthes growers in the world fertilize through the media - not the leaves. There's no point in foliar feeding when you have two other available options that will be of greater benefit.
If you "can't" fertilize the media because you use sphag, A) stop using sphag (a good idea for multiple reasons), B) use an organic fertilizer. Lots of people that use sphag, at least as a top dressing, report benefits to the sphag when using organic fertilizer. Hell, I use inorganic fertilizer (orchid fert) and it has never killed the sphag I have as a top dressing in a couple pots.
Roots and pitchers were meant for nutrient uptake......leaves were not. Or hey, let's do an experiment.Go get 3 ventratas, and spray one down with idk...an oz of 90% alcohol. Then water one with an oz of alcohol, then fill the pitchers of a third with alcohol. The one that was sprayed will survive, the one watered with alcohol will look like hell and may or may not pull through, and the one with alcohol in the pitchers will either just lose its pitchers, but will more likely than not just die. Now what does that tell you?
Nepenthes are not orchids, and have obviously evolved different ways to take up nutrients. Foliar feeding being beneficial to neps because its beneficial to orchids isn't a good argument, and doesn't prove anything.
I enjoyed thoroughly your choice of nepenthes for the drunken nep experiment.