How prevalent was the weighing of booster packs?

Now, I never had a great experience when it came to getting War at Sea booster packs. Looking back at my collection, I could count the total number of battleships I pulled in one hand. I can count the number of 50+ battleships I pulled with two fingers. As for the number of heavy cruisers I pulled... let's just say I could make a whole fleet of exclusively Mogamis. Now, I always thought that I just had plain bad luck (and that may partly be the case), but looking back, I was also quite late into getting booster packs, only starting around 2015, by which time Base Set, Task Force and Set V boosters were all but impossible to get at reasonable prices. (By the way, does anyone know why Set V got so expensive so quickly?) It occurred to me that it'd be rather easy to weigh booster boxes and pick out which ones had the big battleships and carriers, especially given the size difference between heavy cruisers and the big boys. I also purchased all of them online, so it'd be quite easy for more ill-meaning vendors to pick out the lighter ones and send them out. Though, given how niche this game was, the incentive might not be there to do that in the first place. I was curious to hear people's thoughts on this matter.