I've been doing a tiny bit of presenting recently - Teresa's mini-plenary session on imposter phenomena springs to mind. You can find her blog post here.
Personally, I'd be cautious of preaching something (methodology or tools alike) which I haven't tried out with my students. I do talk about teaching theories, but I use them in order to support my critical analysis of methodologies or classroom tools. Fortunately, nobody has said this to me yet: you haven’t actually tried this with your own students though, have you? However, I've already witnessed it happening to other people.
Unless the aim of our talk is to promote a methodology or tool, I think it's important to provide a critical view when presenting in webinars or at conference sessions. This doesn't mean we should be self-defeating, but adding something as simlpe as a qualifying statement would do the job (given that it's based on actual practice!). In the course of developing Second Language Acquisition theories, some methodologies have become fashionable only to be replaced by others. After all, no methodology is inherently good or bad, but rather it's about how effective or efficient they are for language learning, and this depends very much on one's teaching and/or learning context. There's one thing we can't deny though - language is a medium through which we communicate our ideas.
Now, I think we can easily spot an impostor 😁 by asking the 'silver bullet' question, but let's be kind and supportive to them.