I think it would be useful if after a user emerges dev-texlive/texlive-context, they would get a postinstall ewarning or einfo in the lines of: "For using ConTeXt mkII simply use 'texexec' to generate your documents. If you plan to use mkIV and its 'context' command to generate your documents, you have to run 'luatools --generate' as normal user before first use. More information and advanced options on: http://wiki.contextgarden.net/TeX_Live_2010" Reason: ConTeXt in TexLive is shipped with both stable mkII and the more powerful (yet still in development) mkIV. For this reason a stable and standard mkII is enabled by default in TexLive, but in practice most ConTeXt users use mkIV.
Thanks for the suggestion, assigning to maintainers
elog message added, thanks