You've got a fertile imagination John but fortunately it doesn't happen in the way you describe. You don't lose shadow detail. The shadows, where very little activity has taken place, develop out fully early in the development process. In any case, the method involves giving an extra stop of exposure. This is to boost the mid-tones. Reducing development brings the highlights down - as you want to happen - but it also brings the mid-tones down a bit, and the extra exposure brings the mid-tones back up to where you want to see them in the finished print. So you certainly don't lose shadow detail.
The main question is, by how much do you reduce development? Ilford give times which are for "Normal" development. These are calculated to work well for film taken in "normal" contrast, i.e. a bright day with no sun. For film taken in strong sun, a reduction of 20% in development time is generally recommended. You could always start with a 10% reduction, if you want to play it safe.
I say "you" but I know you won't bother with any of this John. I only mentioned this in case anyone here is new to film, and wants to give it a try.