Wikipedia:Don't hijack references

Sometimes when browsing Wikipedia, you'll come across an edit, often, but not always, by an IP editor, in which information has been altered or added to a page, when the previous information was referenced. Now, that's all right; not all references are accurate, new information can become available, and so on. However, in many cases, the altered or added information will be altered or added in such a manner that the citation referencing the previous information, appears to be referencing the new information as well. Altering numbers, as in aircraft performance or production total tables, is a common example of this "reference hijacking"; less common, but still happening often enough to be noticed, is slipping in additional prose text between the period at the end of a sentence and the citation tag following it. This last is almost certainly a good-faith error by newbies, who simply see the end of a sentence and then add onto it. Altering text that is referenced, however, is less easily passed as a mistake, while the number-alteration trick is a favourite tactic of vandals.

Bottom line: don't hijack references. When changing a referenced number, add a new reference, or remove the original reference if it's erroneous and replace it with a citation-needed tag, preferably with an edit summary explaining the issue. Don't change referenced text and leave the original reference; do the same as you would in the first case mentioned. And when adding wholly new information, check for a <ref> tag after the full-stop you're adding the new information afterwards. (Adding new information in the middle of a paragraph that used a single citation at the end is, I admit, tricky, and a good argument for "don't reference a whole paragraph to one cite at the end"...but still, if you're adding something: cite it!)