There are a lot of tab chars in koha-tmpl/intranet-tmpl/prog/en/modules/tags/review.tt The file should be re-formatted to replace them following the coding guidelines.
The staff client templates are full of tab characters, so I don't think we should file bugs for each one. My understanding of the general practice regarding indentation is: - Always remove tab characters from lines which are changed by your patches. - If you want to make other changes to whitespace or indentation, submit a separate patch. Submitting whitespace fixes is always going to create merge problems for pending patches, so we should check http://splitter.koha-community.org for pending patches. It would be interesting if the splitter tool could show a list of templates which have /no/ patches in the queue. Those would be great candidates for whitespace fix patches.
Owen is right stating that we decided a while ago not to clean files globally to avoid conflicts. Tab cleaning is a bit less difficult than perltidy, as it does keep the lines the same and you can use -w to not see whitespace changes.