Why, well a group of us went wheeling and at the end of the day one guys wheel came off and went down the road. The spacer came loose. We ended up checking the other three, they were all loose too. I’m not going to say there wasn’t any error by the guy installing them to start with, but to me it’s just not worth the risk. Double the nuts to check to make sure all is well. Plus the whell gets pushed out and my opinion that puts additional force on the axle / bearing assembly.