Currency symbols seem to have spurious support.

Take for example the Thai Baht symbol.. ฿ which doesn't seem supported in the Thai locale, but is in other locales such as Chinese Simplified..

<?php
$fmt = new NumberFormatter('th_TH', NumberFormatter::CURRENCY);
echo $fmt->formatCurrency(100, 'THB');
// Outputs: THB 100

$fmt = new NumberFormatter('zh_Hans', NumberFormatter::CURRENCY);
echo $fmt->formatCurrency(100, 'THB');
// Outputs: ฿ 100
?>