I have submitted a paper to a conference, but the reviews are not good and the rebuttal is not going well either. So the paper will most likely not be accepted later on. The "intend to submit"/register deadline for another conference will be in a short time, which requires a title and abstract that can be changed later on. The final decision on my paper from the first conference is a few days before the final submission of the second conference.
Is it unethical to register to the second conference and show my intend to submit, while the first conference has not made their final decision on my paper yet? I could still cancel my submission intention on the second conference in case the first conference accepts my paper.