Interesting. APitUE2 says (page 102):

The saved-text bit ... is an XSI extension to the basic POSIX.1 functionality ... and is supported by FreeBSD 5.2.1, Linux 2.4.22, Mac OS X 10.3 and Solaris 9.

But from some of the examples on the Wiki page, it appears that only means the bit exists on those OSs, not that it's actually "sticky".