Interesting suggestion.
It happens I just flew a C-172 the other day that had a "soft" right
brake. When I started to taxi I noticed it, and by pumping it a few times
I regained normal pressure. I tested the brakes several times, and
deciding they were OK, I launched. Before landing, I tested the brakes,a
nd the right one had gone comùpletely soft again. I pumped them a few
times, and all was back to normal. Had I not done this, I may have had a
control issue on landing.

G Faris