If you were looking at the cards juts to check the randomization, you should have informed your opponent of that before drawing the cards.
Without informing him, your actions could only be interpreted by a judge as you not offering your opponent a cut, drawing a hand you didn't like, and shuffling it back in without proper reason.
Prize Penalty at least.
But if I say, "Hey, do you mind if I check to see if I've got cards clumped together" and draw a 7-card hand after getting his permission, showing it to him possibly for good measure, this is perfectly fine?
On the same token, shuffling my deck once or twice, then looking through it, then shuffling it more is also okay?
I've always noticed that I get complete crap hands in RS. I'll play 3 games in a row and get 3 horrible hands, then use my actual deck and play like 10 and never get near as bad of a hand as the 3 on RS...thought it was just me....
I've been fairly certain for a while now that there is a very serious difference between computerized randomization and human shuffling. There CAN'T be a way to actually randomize cards by hand short of throwing them around and having your toddler gather them up for you. You can get close, but the natural clumpage of cards is always going to be there, particularly if you bridge/riffle shuffle and don't do much else.
My hypothesis for this is that when you gather your cards up after a full game, there's a logical procession to your cards because of the way you gather them - Pokemon and Energy are put together, along with any trainers attached to them. Things in your discard pile are all close together, so your supporters, your searchers, etc are near the bottom, and your tactical trainers are further up. And so forth. These become clumps, which you can't realistically clear out of the deck by timely shuffling. Because of this, you tend to draw into more favorable hands when playing with a live deck because the clumpage puts useful cards together - no single card is useful (a Collector) but pairs of them might be (Collector + the Spiritomb your opponent knocked out after you used it), or triads (Dialga, Belt, Call that were all attached at the end of the last game). On the flip side, when you draw bad hands, they're disastrous, because you get UNfavorable groupings of cards: I kid you not when I say I drew into Turn Turn Turn Bronzong Crobat Aaron's Snowpoint one game.
Redshark, meanwhile, is perfectly random, and gives you a perfectly uniform distribution of card draws. That means the clumps are NEVER there, so you need to run a lot more consistency cards to make your deck function.
This is why I am such a stickler about Call Energy and other consistency cards in every deck when others debate their usefulness: I test almost exclusively on Redshark, where you're just as likely to draw Call Energy early as you are late. For others, because of the way their deck gets grouped after games, they may draw Call later on and it becomes dead weight - and they won't need it as often anyway. I know I certainly regretted running Call last weekend!
EDIT:
Toxictaipan said:
I intentionally clumped 6 cards together and shuffled my deck for 10 minutes (I know I'm being trolled, but I just wanted to test it for my own reference), using various shuffling techniques, including topping it off with a single cut at the end. Results: Near the bottom of my deck, there was a clump consisting of 2 copies of the card, followed by 1 copy only 7 cards away from it. As I went deeper in my deck, there was a another clump of 2 copies at about the top half point. The fact of the matter is, while you can break up a big clump of cards from physically touching each other, it's going to be hard to get those cards far apart from each other, and even harder to separate 2 individual copies of a card from touching each other.
This test is a demonstration of the concept I just outlined - I hope to do a more comprehensive test later, maybe next week, and actually use some statistical analysis on the 7-card hands I draw. But TTP's little test is a nice example of what I'm talking about regardless: your cards tend to stick together in the deck no matter how much you shuffle.