I'd like to know how I can exclude or prevent visitors from entering both experiences in my Target activity. I am currently using Adobe Target as my reporting source, and I'm wondering if there is an OOB functionality to segment those visitors who saw both experiences and exclude them out of my activity.
I'm only trying to be proactive because sometimes this issue persists in A4T and I end up needing to create exclusion segments because the total visitors adds up to >100%.
I presume you are talking about an AB test? In this case visitors are not meant to change an experience. I suppose there may be some rare cases where it could happen, but they should be rare. If you are talking about an XT (experience targeting) activity then it is certainly possibly they can qualify for a new audience later and therefore qualify for a different higher priority experience.
As for Target reporting source compared to Analytics reporting source (A4T) for an AB test. There can be some cases with A4T where it appears like visitors are in multiple experiences especially for redirect offer experiences. These reporting nuances are unique to A4T and aren't relevant to Target reporting. So I don't think you'll find the same need to create an exclusion segment with Target reporting.