As long as they don’t get pollen sacs, go for it. Observe carefully! Worst that can happen is you get a plant ‘pregnant’.
In the old days there were always seeds in the buds.

I hope you are only partially trimming the tips as you may be suppressing flower formation. One week of distractions could get pollen and then seedy harvest. Another year learn to take cuttings, you can test flower the cuts before they even root. Just put them on 6 or so hours of light, 16-18 hours of darkness per day will get the cuttings to show gender. That way you can start with more seeds and pull the males early. You can even keep a few male cuttings and flower them tiny, harvest the pollen and selectively pollinate just a small bud area on a couple of plants.

So I can't control the hours of light. I'm only pinching the very tips.

Then control their dark period, long dark periods greater than 16 hours will get them showing gender rapidly. If you kerp track of which cutting came from which outside plant you can figure this out quickly. They can show gender before they even finish rooting. This was a tip especially for subsequent years, as you can then only grow females, which helps if you face a plant limit. And even if you just have an area limit you can reduce seeds happening.

All the work it took breeding to different strains. Helped my mentor breed for a few years, it was fun but a lot of work and worry.
Grew a seed from my last project this year, just harvested today. Posted results in Cannabis. Cross between Humboldt’s Autoflower Magic Melon and a male auto of an unknown strain. Got the pollen from a friend who grows amid he forgot the name, it was really good stuff. Stoners memory.

https://www.democraticunderground.com/127912163