Agreed...it is "improper" to use /tmp as a source for installation images (usually "/usr/sys/inst.images" is used), nor is it appropriate for long-running logs (like the syslog, which should go in "/var/adm/ras"). Letting /tmp fill up is a Very Bad Thing.

However, I would not just delete the contents of /tmp willy-nilly. There are some programs that use it for, well, temporary space. So doing a mass-deletion should be limited to files/dirs that are old (i.e., 30 days).

There should always be some sort of /tmp cleanup that is automated, such as "skulker".