One might like to think that Highs were numbers but they're not, even when they're on a map. One would be correct to say the surrounding isobars had numbers indicating the barometric pressure each line represented. One would even allow that the value of the local pressure maximum under the H symbol would be described with a number, but a High ain't a number despite what 6 Down would make one believe. Isn't it funny how we expect such precision in our clues and we're disappointed when they don't measure up? But puzzles force that on us when they use cleverly misleading clues that require precise parsing to solve. They can't have it both ways.
And what's with the propensity of puzzles to use "one" as an indefinite pronoun? In today's puzzle by Joe Krozel (answers) we clue CRANE as STRETCH ONE'S NECK. This same puzzle accepts PLOTZ and LOTTA as acceptable answers but we're suddenly all faux-Brit formal with ones? "Stretch your neck" has the same number of letters.
I have generally admired Mr. Krozel's constructions. I raved about his recent ones already in this blog so I'll mention two others. This one from August 2007 (Across Lite, answers) is memorable. The print version listed all clues in a single list, not separated by Across and Down. Another one from earlier that same year (Across Lite, answers) was great fun to solve.
Update: Check out the first comment below where Orange makes the perfectly reasonable case that Highs can, in fact, be numbers. I hadn't thought of it that way.