On behalf of Adobe …
Very Seriously! If you have a “printer” who requires outlined text, you (or perhaps a client of yours) should be looking for a new printer!
There is absolutely no good reason for a print service provider in this day and age to reject a PDF file exported from InDesign using the PDF/X-4 export settings allowing for (1) live transparency and (2) use of ICC tagged RGB content where appropriate as well as “live text” referencing subset-embedded fonts.
The fact is that no RIP/DFE used for making printing plates (for offset or flexo) or directly imaging a digital printer cannot fully and properly handle “live text.” In fact, all “outlining text” yields is bloated PDF file size, increased RIP times, an inability to search or do PDF text touch up, and in many cases, degraded print quality.
The only time one should “outline text” is in situations in which you need to do artistic transformations of glyphs that are beyond simple changes of color, rotation, size, etc. Highly-stylized logos using text might qualify for such a situation where outlining text may be the only way to achieve a particular graphical effect.
Then, why do we keep on hearing about printers who “require” text outlining (or pre-flattened transparency or all non-CMYK content converted to CMYK)? The basic reason comes down to lack of training or keeping current with modern end-to-end PDF publishing / print workflows. Perhaps the personnel involved got into the industry in the 1980s or early 1990s or learned the trade from someone from that era and have not kept up in terms of training as to industry best practices. Or maybe you are dealing with modern day Luddites?!?! Whatever, I'd be more that happy to personally help educate such printers!
Either way, if you are dealing with such printers, there is a very good chance that things can go very wrong in terms of the printed output you receive from same. You've been warned!