One does not NEED to palpate but knowing how many eggs will be coming is awesome.

I palpate every snake I breed numerous times throughout breeding and I have dropped over 60 eggs so far this season with one partial slug in a 10 egg clutch and it will hatch with no issues.
I also palpated every snake I bred last year too and the only slugs came from a malnourished female that had eggs before I bought her.

I don't think palpating them has anything at all to do with making slugs