When I see the word Sukot, it doesn't even look to my "mind's eye"
like a word with a long "u", it reads to me a "u" sounding like the
"u" in the word "suck". For the word to sound like a long "u" and
have only one consonent, I would need it to be spelled "sookot" -
which looks ridiculous.
That is how ingrained the spelling of Sukkot with double consonent is, to me.
Shoshanna Walker
A convention in this case is the way most folks do it, and as
Shoshanna has demonstrated,
this one is most definitely a convention in transliteration.