Is there any indication for hydroxyurea in patients with sickle cell trait?

No.

Of course, be sure it is the correct diagnosis and not HgA + HgS (beta+) which, as you know, shows HgA and HgS on electrophoresis and can/will be called trait if not looked at by someone experienced to note if A> S or if S > A. If MCV is low. If HgA2 is up. HgF up etc... If indirect Bili/LDH/AST is up...

The reason this is so important, is there is a substantial mis (dis?) information about sickle trait as a disease.

It's an important part of equity. See slides 68-72 where I discuss this directly:

The Knowledge Gap No one Talks About: The Care and Understanding of Sickle Cell Disease​

Or

Be aware

1. High performers at the (very high altitude) Mexico Olympics of 1976 in the marathon and other sports with sickle trait and no consequences a ...

There is no indication for hydroxyurea. Individuals with sickle cell trait are not expected to sickle (no HbS polymerization) at sea level and low altitudes. Sickling complications may occur at high altitudes and in other extreme circumstances associated with exceptionally strenuous exertion, severe dehydration, and heat stroke. There is also recent evidence that sickle trait is associated with a mildly increased risk of pulmonary embolism (similar to the risk conferred by heterozygous factor V Leiden), CKD, and leukemia (OR for ‘any leukemia’ was 1.48 (95% CI 1.27-1.73, p < 0.0001), Sostin et al., Blood 2023. Nigel Key and Rakhi Naik have several important publications on this topic. In any case, the risks I have outlined above do not warr...