Tosafos 39a writes that one of the solutions to ensure that one is going to be making the bracha prior to performing the mitzvah of lulav is to intend to NOT be yotzei by lifting it up until after the bracha. Tosafos is confident that this works, since even according to the opinion that mitzvos don't require kavana, when one has intent explicitly NOT to be yotzei, he is not yotzei.
The Biur Halacha (cited in my sefer nasiach b'chukecha pg 129) writes that if one is accustomed to always counting sefira after tzeis hakochavim, and is asked by someone during bein hashmashos what night of the omer it is, even if they responded with the correct number they can count later with a bracha. The justification is that even if mitzvos don't require kavana, since this person always counts later, it is as if he is intending not to be yotzei when he tells his friend the correct number.
To extend this sevara one step further, perhaps one can argue that when one is accustomed to always doing a mitzvah with a bracha, until they actually make the bracha it is as if they were intending not to be yotzei. In other words, if the biur halacha is correct that we can look at the persons general practice to consider it as if he were intending not to be yotzei, we should be able to look at the absence of the bracha as an indication as well.
There is a clear proof from Tosafos that this is incorrect. The gemara on 42a struggles with how to find a case where a person is carrying out a lulav and will not be yotzei. Tosafos asks why don't we just say that he isn't yotzei since mitzvos require intent and he is not intending to be yotzei. Tosafos explains that since he isn't making a bracha now, it is clear that he is not intending to be yotzei. The implication of Tosafos is that according to the opinion who says that mitzvos do not require kavana, the gemara works out fine. But why don't we say that even according to the opinion that kavana is not necessary, he should not be yotzei by carrying it out. The rationale would be that since he is not making a bracha now, it is as if he intended explicitly NOT to be yotzei because his practice is to always do this mitzvah with a bracha. Clearly, Tosafos holds that although explicit intent to NOT be yotzei would work even according to the opinion that מצות אין צריכות כוונה, but by merely not making a bracha we CANNOT interpret his intent to be as if he were intending NOT to be yotzei. Tosafos assumes that if mitzvos don't require intent he would be yotzei, and that is why the gemara needs to struggle to find the case where he isn't yotzei.