There is a rule on StackOverflow: If your code turns out to not have been working as expected simply because you misspelled a variable somewhere, the question is considered off-topic.
This is a reasonable rule: Indeed, how is such a question useful to anyone but the author? It is unlikely that anyone who comes from a search for "I tried to do X but couldn't, why?" will happen to have made the same mistake.
In this question the user is asking why their DNA bands are too faint. It turns out that the problem is that they used the wrong illuminator - a blue LED meant for CYBR Green, not a UV for EtBr.
I don't believe this question would be useful to other people who come trying to figure out how to make their bands brighter. In my answer, I've listed several reasons for faint bands, note how none of them (with the possible exception of the very broad #3) applies in this case.
The question "How can I make my bands brighter on an agarose gel?" assumes that you've performed the agarose gel electrophoresis correctly. For instance, trivial answers like "don't use the wrong illuminator" or "don't use agar instead of agarose" or "don't forget to add the EtBr" should be precluded.
Or should they? Should the linked question be considered off-topic, by analogy to the StackExchange rule?