You do take notice of responses like you said yourself, though you never outright ignore. And you can do things about it if you choose to, you just skip the part where you try to decide where it came from when you don't have enough proof of it going either way. Especially when it comes to people like you who need definite proof now now now hurry, the main issue is noticing something that is a tupper and then going "nah couldn't be tupper because it was too x", when we most likely will never have the ability to know that for sure. The issue is that you could potentially be blocking and ignoring actual responses from a tulpa because of your own insecurity or close-minded beliefs. And once you ignore the feeling you deemed as "fake"? You'll keep ignoring it even if it keeps happening because you have already decided it's not legit, even if it's actually the tupper trying to contact you. It's a pretty toxic mindset.
But blindly believing is just as toxic, which is why we are trying to avoid it. You know where it leads, don't you. But it's like you're trying to create this fluid state where not only will you notice strange things and become more receptive, it's also hopefully going to create an environment for the tupper where they know they can try different things and be noticed. You don't want to shoot down someone's early attempts at trying to communicate with you, basically, and I already talked of the issue of starting to ignore possible responses. You acknowledge things. You can talk to the tupper about it and ask if it was them, maybe try listening for a while to see if you get a response of any kind to that - though you can also say that if it wasn't them, it's still fine, you're not trying to force this kind of things to come from them if it wasn't the case. At the same time you're also trying to treat the tupper as a human being while giving yourself the opportunity to not just believe everything. Like man, a tupper could be annoyed if you got a very thick skull and never seemed to notice or never believed after they have done everything they can, but be nice and I hope that means hosts can be forgiven. I think doubting and wondering is normal, so it should be understandable even if it feels unfair from a tupper point of view.
Absence of Disbelief is a mindset, not a set of certain things you must do in this or that order. It's not a guide. You do things when you feel like you can do them without shooting yourself in the foot. And "doing" something isn't necessarily deciding whether or not the response came from a tupper, mind you. It could also be experiments and anything else you can think of. Making tuppers is such a personal process that there's no one person who can tell you what to do, you just have to try different things and see which ones help you the most. But I suggest experimenting and tackling it as a study of sorts without being totally unethical about it or anything, but do it for the sake of both you and the tulpa. Make it fun to both of you. A game of sorts.
Life ain't black and white. You won't get much proof of anything. All you got are your own experiences and like I said earlier in IRC, your experiences and memories only prove that you thought you experienced something as they can become corrupted over time. Or just start out corrupted because you never saw the entire story, you know? We don't know for sure if tuppers are actually sapient or if they are just automatic parrots. You can't know for sure that I am sapient, either. You'll never get proof, and Absence of Disbelief is about leaving the black and white mindset behind and realizing that there's only different shades of gray. And most importantly, you go through the tulpaforcing process at your own pace, giving yourself as much time as you need to decide if you think you can trust your tupper and the responses you are getting. I know I got a pretty great guy talking to me in my mind by adopting such a way of thinking, at least.