I'd be more suspicious of a person coming to my door purely just to educate me on cool science things. I wouldn't be able to shake the feeling that he's trying to sell me something.
At least with religion I know their game and I know I'm not interested but science that's interesting.
I'd be more suspicious of them telling me life exists on Venus, specifically. Last I heard it was a hot-ass gaseous atmosphere made of acid. My money is still on Europa.
Only because they often are... which is what makes science so great. If everything was thought to be correct, what good would testing and new discovery be? The fact that scientists have historically been wrong drives scientists to prove other scientists wrong.
"I [Carl Sagan] can remember one occasion, taking a shower with my wife while high, in which I had an idea on the origins and invalidities of racism in terms of gaussian distribution curves," wrote the former Cornell University professor. "I wrote the curves in soap on the shower wall, and went to write the idea down."
Also, I would say a lot of modern medicine, since the discovery of germ theory, has included a sizeable portion of evangelism. How do you think they got people to start washing their hands or taking antibiotics?
It's a two-edged sword: yes, you're probably doing great work, but on the other hand it might come off as annoying and give science a bad name.
I wouldn't mind some random knock on my door once a week or so by someone who wants to sit down and teach me some random scientific principle or spit out fast facts. One would have to watch out for false priests though. "did you know that vaccines are nanobots injected to support Bill Gates?" or something.
YouTube already does this in a less invasive way. "Here's this random video on theory crafting how we can put life on Mars that we just thought you might like."