Yep correct it's not throttling, I'm not sure what the exact term for it is but you get the gist. In my mind, parsonjack's write-up is inconsistent with that view - surely it's not device dependent but network dependent?
If it's IP restricted, then are we saying anyone who lives in a small block of flats, anyone who is sharing the same WiFi connection in some sort of campus and anyone working in a small office only has one 'real' chance of getting through? I'd be amazed if it's been set up like that purely because of that problem.
I'm not trying to cause a feud here, no need for the aggression. A network engineer above agrees with my logic. I've read parsonjack's test regarding the load balancer sending you to different servers, which is 100% exactly how it will be working at SeeTickets, but I'm not sure I agree on the conclusion. Great though the test is and is far more than I've done, and he/she clearly knows more than me! That doesn't mean I can't point out perceived flaws in the logic and if they can show me where I'm wrong then that's even better.
Another thing to throw into the mix is the fact that anecdotal evidence suggests those tethering from mobile networks have had more success. This goes against the logic that the more devices at a single IP address = less of a chance, as absolutely loads of people will be sharing the same IP in this scenario.
I'd say we all are 100% in agreement in multiple devices on as many different Internet connections as possible seems to be the safest route. I.e. laptop on home network + different laptop on work network + different laptop tethering from mobile, etc.
Fact is, none of us have a facking clue!