I've been chaining since at least May 2008. Over time you just know what to do. It's really easy, nearly every chain I do results in a shiny. My highest chain ever actually is 212 Nidoran Male, 19 shinies came from it.
My Floatzel is from a close IRL friend, so I know it's proper. As for the Golem, since it's such a common Shiny and it looked quite innocent, I don't have much of a reason to doubt it.
As for PokéRadar Shinies, how is it any easier to do now than before? Did something happen while I was away? Both my chained shinies are common Pokémon in their routes (Starly early on, Zubat at night), but other than that, I can't see much of a way to cheese it.
Hah, that reminds me of a Latios I have in my possession... Got him off the GTS - Silverbolt, Lvl 99 Latios with perfect nature, HP 70 Fire and, when I got it, it had been transferred from Hoenn and levelled allllllllll the way from 40 to 99 in one day. Uh huh. Well, least to say, I've been toying with it with a friend of mine, trying to make a pseudo-legit Shiny out of it by using Random.org to roll for new IVs and nature and then giving it a fitting PID to fit that spread. :D
Yeah, that's what I'm aware of as well. Coding's a bit hard to cross, while random "ZOMG CHECK OUT MY REAL LIFE HAXXED SHINY!" claims are annoyingly common - YouTube is infested with those kinds of videos. :p
By the way, I've been researching those Shiny flags. Serebii seems to say the Dragonspiral Tower Reshi/Zek can be Shiny, but people seem to have gone into the coding and tested it with RNG and say neither that nor the N's Castle ones can't be Shiny. You wouldn't happen to have found any conclusive evidence, would you?