To be fair, the risk of being blighted isn't as high as some people seem to be presenting it. If you get darkspawn blood within your system via open wound or mouth, you will be corrupted no doubt. If you're just in the near vicinity of darkspawn, it will take a little bit of time before the corruption spreads to you. Darkspawn corrupt living and non-living matter by virtue of proximity, but that doesn't happen within 10 minutes. It takes days, weeks, or months depending on what that thing is and how nearby they are.
Even swords or shields getting bled on by darkspawn does not mean instant death or corruption. Blood can be scrubbed off after a battle and the cleaning materials burned. Fire or high heat is apparently a purifier when it comes to potentially tainted objects (or darkspawn corpses), so a helpful mage could probably get some fire going to assist in the cleansing.
Remember The Messenger from Awakening? If you let him live, he becomes Batman and helps travelers and stuff. Not everyone dies if he helps them, but some people do become infected, and if he stays in one place for too long, the ground/general area he was in becomes tainted as well.
Not to mention the dwarven population of Orzammar. Dwarves fight darkspawn all the time, but if there was a 100% chance to be tainted by fighting or being in potentially corrupted areas of the Deep Roads, you'd think the population would have entirely died out by now.
There is zero chance of any main companions of Inquisitor getting blighted, but perhaps one of the two dwarves will. If Bioware was smart, they will have at least written dialogue for either the companions or the Inquisitor to remind everyone of the dangers of darkspawn, to not them bleed on you, and don't touch the icky black goo on the walls. Our Legion of the Dead friend will most certainly have something to say about reducing the risk of being tainted, if only for the benefit of the player.