Since this seems to be a hot button topic for the moment...here's my two cents:
Blind theft is completely and 100% a necessity but the method in which one goes about it is completely and 100% determined by the particular style one wishes to employ.
If you want to be a maniac, then by all means, get your hands in that cookie jar. Sometimes you'll get caught, like for instance if you raise J7s in LP, get flatted by a blind, see a J high flop and it checks to you...you bet, get check/raised, decide they're full of it and shove only to see that they have a better J. That happens, and that's just part of the style...it's dangerous but effective if done properly.
If you want to be a tightwad and "steal" only with good hands...well then you're going to dominate somone who flats with JTo from the blinds when you raise AJo in LP and you both flop a J. That happens, that's just part of the style, it's not dangerous but is also very effective if done properly.
The best thing, IMO, is to just figure out what type of player you want to be and learn how to maximize your profits within those guidelines.