Yes.
But for how much they increase the syn value, I don't see an issue adding those syn on personally.
For example, the Lemon Drizzle cake recipe that's floating around on here somewhere was 8 syns for the whole cake, but it used 6 tbsps. of sweetener (I think!) which would add 3 syns.
The whole cake would now be 11 syns, which in fairness still isn't bad!
It's just up to each individual person to syn things correctly. If they don't want to because they know they don't eat a lot of something, then it's up to them.
Personally I syn everything when I'm on track properly, and I've never been a fan of tweaks either, but that's just me