The definition does not imply this. Neither RepRap G-Code reference nor LinuxCNC G-Code reference nor Wikipedia mention any correlation of G28 and G92. And believe me, on a CNC-mill it would cause trouble. Having to rehome an axis does not necessary move your vice or workpiece on the table. Telling the machine were the work piece is on the table is what G92 was made for. What you store with G92 can be the result of an hour of measuring and sometimes even not be recovered after something is milled.
I think it'd be a bad idea to change this in printers' firmwares. Someone could take a modern (fast enough) CNC-mill and put an extruder in a chuck. Don't brake this. We love standards.
So the plugin has to deal with that. And this means the print file has to set the offset back at the end. Of cause this is not ideal as someone might interrupt the print. As we cannot change that, doing the G92 manual is better. People should be encouraged to do so.
If you're to lazy to jog and always have the same offset, then a file with
G28 X Y ; home X and Z
G0 X-35 ; Change the value to your needs. Homing Z shouldn't crash the extruder on you bed.
G28 Z ; home Z
G92 -<_offset> ; where <_offset> is your desired offset. If 0 is not your home position change
; analogously.
You can have both files on the SD.
Today I got a new glass plate from China. I was printing on a small piece of junk glass before. I already had the next print which would have been to big for the junk glass on the printer. Well, when the print from yesterday was done I measured the new glass thickness, calculated the offset, swapped the glass, jogged to the calculated new offset, ran my one liner and started the next print. This is quick. No need to unmount the SD, mount it on the Desktop, change the file in an editor or worse reslice it, unmount the SD, mount it on the printer... Someone could just spontaneously decide to use painters tape (+0.1mm) or something else or the plywood carriage under the bed warps... and quickly need a new offset.