A very valid point. Most of the raiders are unaligned and are extremely well below the NS range of 3,000, it is highly doubtful that they would be even aware of a tech raiding moratorium then suddenly, they're getting hit because they attacked an unaligned nation and being informed that they cannot raid. From what I can see at that point, it's a double edged sword, raiding the raiders and the raiders would be pushed of the game as well. Raiding is a game feature and personally, I do not think raiding people would lead the "victims" to quit, they would be more likely to find an alliance and seek protection.
Overall, I do not think imposing a moratorium on tech raiding would help, given limitations there. If any, taking away a new nation's ability to war and raid for a certain amount of time (4 weeks) is far a much better "solution."