You're referring to human error, if you can orginise yourself to carry more smaller cards its technically safer.
Do you mean technically, or mathematically?
Mathematically, the more cards you have, the more likely you are to have a failure. Here's an example...
Suppose the probability of failure of a single card is 0.1 or 10% (way over-estimated to make it more obvious, but the same will hold true for any number).
If you use a single card the chances of not having a failure is 0.9
With two cards it's 0.9 x 0.9 = 0.81
With four cards it's (0.9)^4 = 0.65
With 8 cards it's (0.9)^8 = 0.43 - you're more likely to have a failure than not.
Now I reckon the failure rate, for me, must be lower than 0.0001 because I must have used CF cards over 10,000 times. So the chances of me not having a failure are 99.99%. But if I were to use 8 cards that would drop to 99.92% - still very unlikely, but still 8 times more likely than when using a single card.
If you mean techically, well, technically, the most common way of ruining a card is when inserting it into its interface. That will happen more often with smaller cards. The second most common way of damaging a card is actual physical damage (dropping it, sitting on it). Again, this is much less likely to happen to a card in the camera rather than in a pocket.
Oh, and as for human error - do you know anybody who's not capable of that?
