You might text these to someone:
Walking to school.
I believe that the main use of this type of sentence would be to describe what you yourself are doing in that moment. You might write this on a dating profile:
Seeking openminded, Christian, bowling fans.
So, my question is, are these full sentences that should start with a capital letter and then be terminated with a period? There are no subjects, and unlike usual imperatives, they don't give commands . . .