I don't think that's a major issue. It should be straighforward to disambiguate: make separate units for imperial pint, liquid pint, dry pint, etc. If this is cumbersome, provide an option to set aliases for these in a meta tag, for example. If the writer of the document is sophisticated enough to be using these tags, they should be sophisticated enough to look up what the proper name is for the unit they're using.

> If I write 1 pint do I mean an imperial pint, a US liquid pint, or a US dry pint?

Since you are writing it you must know it and you can choose the correct tag or attribute for your html

I'm confused. Why is that a problem?

If I need to pay and the price is in 'Dollar' I assume the recipient can clearly indicate if it's a USD or a AUD that he wants to receive here. Francs and Swiss Francs shared the same name, but were different things (and had different abbreviations).

The same would be possible for the units you mentioned.

There's a nice one at http://thedailywtf.com/Articles/Do-the-Math.aspx : "keeps your vehicle up to 44˚F/7˚C cooler"