I really do think it's naive to think that Katy is ripping off Gaga just because there are a couple of mild similarities between a few creative ideas, and also a bit rich, given that the 'affected' fanbase is one who has gone through hell and back trying to defend their fave whilst Madonna stans from all corners of the internet have been dragging together comparative photos, costumes, ideas etc between the two ladies for years, much to the chagrin of Little Monsters worldwide. Hell, if I set my mind to it, I could probably try and create a convincing case that Emma Watson is ripping off Queen Latifah at every corner - it's the nature of everything being everlasting on the internet.
I mean, really. This isn't 2009 anymore - Gaga is not the fresh, titanic, influential character that she once was. Just stop and think. Do you seriously think Katy saw Gaga don a seashell bra, and immediately ran to the designers of her tour, saying 'Well gosh, Moschino! That Lady Gaga's got everyone around the globe absolutely BUZZING about the fact she's put seashells on her tits - let's TOTALLY copy that, but make them leaves instead!!!!' No. And re: the tour interlude (which may have been filmed weeks, if not months ago) do you really think Katy thought people would respond a) warmly, and b) at all to a 'supposed' rip-off of Gaga's paint vomiting that, crucially, is actually really nothing like it at all? As has been pointed out, popstars and paint are not a new concept by any means.
Am I trying to claim that Katy is a visionary, creatively innovative artist? Far from it. And am I trying to deny that Gaga has probably influenced some of Katy's creative decisions in the past (hello, cheese cube hat)? No. All I'm saying is that when you think really sensibly about it, it's very doubtful that Katy's especially interested in any of Gaga's creative decisions any more, let alone ripping them off.
This is not an attack on Gaga, and not a particular defence of Katy. It's just a dose of common sense for hysterical fans who have probably composed videos claiming that Katy also copies the way Gaga blinks at 0:52 in the 'Judas' video. What's the point?