I took some time this afternoon to check and re-adjust my tire pressure as I periodically do, and gave my dad a hand with the same task on theirs. We also took the time to check the spares as well, and they were certainly low. One was at 50 psi, while the other two were in the low 40s. Not the worst I've found though - I've found them at ~24 psi before.
I keep a bicycle pump with me regardless, but it is nice to only need to bump the pressure up a bit if the spare is needed rather than need to fill it from near empty with said bicycle pump on the side of the road.
Also an amusing note - all three spares are size 145-80 D17, and all three are different brands and countries of origin. A USA made Firestone, a Japanese made Bridgestone, and an Indonesian made Falken.