A balanced socket, input or output, can be used using a TS-fitted unbalanced cable for an unbalanced connection. A TS plug will shorted R and S on the TRS socket which means the inverted (cold) differential signal and ground.
For inputs, that's how to do things.
For true inverted outputs, this will mean halving the available output level, for servo-differential or resistor-only outputs (the latter don't carry an actual signal but have the same impedance as the hot output) the level will stay the same.
Note that the opposite, using a TRS cable in a TS socket, is less well-defined and also the cable's internals are not matched to the use then. So if either of your end sockets is unbalanced, use an unbalanced shielded cable with TS connectors.
To answer your question: taking an unbalanced source, splitting the channels and feeding them into two separate TRS sockets using TS jacks is pretty common. If the input is a stereo TRS signal (like a headphone socket, usually not actually a good match in impedance), using an "insert cable" would usually do the job: those are TRS to twice TS.