Are silicone travel bottles actually leak-proof in checked or carry-on bags?

The high-trust consensus across r/onebag and r/HerOneBag threads is that quality silicone squeeze bottles (humangear GoToob+, LiquiSnugs, and well-reviewed Amazon sets) rarely leak in carry-ons, but thin liquids like mouthwash and very oily serums are the most common failure modes reported. For oils and serums, reviewers consistently recommend small rigid bottles or capsule-style containers over silicone squeeze tubes.