I agree I have tried to field install plugs even with a Pallidin tool, that the wires go thru the plug and are trimmed off. Its hard to do. If the light is not good I get the orange and brown mixed upBut they do know what other wire they are twisted with.
These are the bozos who give us a bad name. Either learn what the color code is for 568A and 568B or don't do it at all.
And, you should know that I forbid field installing RJ-45 plugs.