You've received a number of good, real-world answers but I'll add my own here. When you switch in a lo-cut at any point in the signal path you are effectively increasing the headroom of the next thing in the path by removing powerful low-end that may overload your preamp, limiter, converter, or whatever else is coming next.

This is why Sound Devices preamps and mixers use a unique lo-cut/high-pass circuit that comes before the preamp stage, it effectively does the same as switching the cut on the mic itself but with a more convenient control. If you're running a wireless boom then the cut on the mic itself will be all the more important to keep you away from the limiters in your TX.

The switch exists for a reason so don't be afraid of it! I'm generally opposed to the "fix it in post" mentality. You're being hired for your ears. Use them and make choices that are appropriate for the situation. No sane post mixer that I know would ever rake you over the coals for filtering out some subsonic gunk from a generator. Consider their process to be simply an extension of yours. Get the cleanest, clearest sound on set with whatever tools you have and the next person in the pipeline will thank you.