All I will say is, don't expect future versions of Mach to work that way.

Ok...  I tested it on my machine, and on my desktop that has no machine connected.  It seemed to work the same way on both.  I think my desktop has the latest version of 3 as I had to nuke the computer (ice virus) and reinstall just a week or so ago.  It is also the way Tormach documents to setup their machines, so its not something new I just discovered.  G28 to preposition for a tool change. T(x) M6 G43 H(x) to perform the tool change.  

G28 is defined in the Mach 3 descriptions as "To return to a home position by way of the programmed position," and "If no axis words are programmed, the intermediate point is the current point."  On the homing and limits page there is a place to enter the G28 position.  Based on the documentaiton it sounds like its doing exactly what its supposed to.  I do have safe Z turned on.  I suppose it would go directly to that position and risk crashes into clamps etc if I did not, but otherwise it seems like its doing what is described.  

Are you saying that I have grossly mis-interpretted the documentation, or that you are redefining the meaning of G28 in future versions?  

I had not used G30 before, but based on this thread I decided to see what it does.  G28 seems to utilize a safe Z, and G30 seems to go directly to home without utilizing a safe z move.  Otherwise they both rapid the machine to the programmed position when no axis words are used.  (I have not tried it on a machine where safe Z is not programmed.)