I think the simple answer is that it isn't really supported for annotative objects. It will have worked. The text will have been created, it's just that it isn't visible until you add an annotation scale to it or make it non-annotative.
The command OBJECTSCALE (and with PICKSTYLE set to 1 or 3) might help her to bring the text back once the textmask is done by adding a scale, though that will only work in model space, not in paper space. And, as roy_043 alluded to, if you leave the text as annotative then that won't solve the problem where someone later changes the annotation scale and the raster image "wipeout" behind the text stays the same size. Alternatively, make the text non-annotative.
If she doesn't want to move to using MTEXT, you could look at modifying the textmask.lsp routine yourself if you are up to it. It is the extended data of the original text that defines it as being annotative. If you removed that xdata data prior to the entmake call it would solve the problem.