Comment by JR1427

Images like this show how specifically the antibody binds to the antigen. Generally, the ideal is to have very specific binding. As such, this type of image (Western blot) would only have single bands in any vertical lane. Any other bands show that the antibody is binding to other molecules.

The evidence of painting out the background is likely someone cleaning up other bands, where the antibody has bound to something other than the intended target. So, they are making out the antibody is better than it actually is.

Copy-pasted bands could be evidence of attempting to make a weak band look stronger, or even adding a band where one didn't exist - potentially the entire blot is fabricated.

Either way, like someone else said, this is like fabricating parts of a data sheet.

It doesn't excuse it, but like someone else said, scientists would never just trust an antibody they bought. They'd do their own tests. Labs will also share notes amongst each other, along the lines of "that antibody is bad, and also strongly binds XYZ. You should try this other one instead".