I'll use this to also mention lolicons and proshippers in general

It depends on the artist, but I noticed that multiple times I was able to clock an artist as proshipper even if they were drawing SFW stuff, mostly by how vague their descriptions can be, how chill they are and how they draw an adult and a child being too close or the child being a bit flirty, almost kissing the adult, or wearing skimpy clothes or still suggestive clothes...
Or the artist draw stuff that antis wouldn't draw like specific ways to make an adult and a child interact even if it's SFW or violent content in a way that isn't interesting for certain antis

But it really REALLY depends