In my experience, I've never seen more than "pipette 100 μl" or at most "caution viscous liquid". Also I've only been taught how to pipette in a general manner and never about how to do it with special liquids except for the "cut the tip off" advise so before Noah's answer I had never heard of reverse pipetting or using a multivette to accurately pipette glycerol for example as described on the eppendorf website. However, when pipetting glycerol for example I could tell that I needed to pipette it slowly and I could check visually that I had (about) the right volume using the marks on the tip. So compared to a robot I can use my eyes to adjust and it's good enough in my particular case and with a single tube it is not optimal and it may not hold true with a multichannel pipette so having good and better pipetting habits would be better for reproducibility.
Now if I can see the "cut the tip" advice and the standalone "pipette 100 μl " instruction work to some extend, "commercial" grade protocol would probably have the instruction written as "using a multivette (or using the reverse pipetting technique) pipette 100 μl".
Another thing to consider is the definition of protocol which if we take wikipedia's definition is not just a succession of steps to perform :
In addition to detailed procedures, equipment, and instruments, protocols will also contain study objectives, reasoning for experimental design, reasoning for chosen sample sizes, safety precautions, and how results were calculated and reported, including statistical analysis and any rules for predefining and documenting excluded data to avoid bias.
What we usually consider as a protocol is the "Quick protocol" with only the steps to perform where you're more likely to find the "pipette 100 μl" type instruction. But if you consider the more detailed protocol you'll find more information. I don't have an example for liquid handling but if you consider the qiagen miniprep protocol depending if you take the quick version or the full one you may not be doing the same thing. Let's take step 2 as an example :
Add 250 μl Buffer P2 and mix thoroughly by inverting the tube
4–6 times until the solution becomes clear. Do not allow the lysis reaction to
proceed for more than 5 min. If using LyseBlue reagent, the solution will turn
Add 250 μl Buffer P2 and mix thoroughly by inverting the tube 4–6 times.
Mix gently by inverting the tube. Do not vortex, because this will result in shearing of
genomic DNA and contamination of plasmid. If continue inverting the tube until the
solution becomes viscous and slightly clear. Do not allow the lysis reaction to proceed for
more than 5 min.
If LyseBlue has been added to Buffer P1, the cell suspension will turn blue after addition
of Buffer P2. Mixing should result in a homogeneously colored suspension. If the
suspension contains localized colorless regions, or if brownish cell clumps are still visible,
continue mixing the solution until a homogeneously colored suspension is achieved.
If we consider only the mix part here, "gently" is the key word. If you've been handed only the quick protocol and you're an inexperience user even just by inverting too strongly you may end up shearing the genomic DNA and thus contaminate your sample what can impact your downstream application.
So the bottom line is that "pipette 100 μl" may be enough for experience users and/or some applications on a quick protocol but you may also want to have the instruction "pipette 100 μl using a multivette (or using the reverse pipetting technique)" on a more detailed protocol for inexperience user or troubleshooting purposes.