Rebbe,
If we follow Rebbe Akiva and pay all 5 women and/or all 5 merchants aren't we encouraging more geneiva? Four of the women and four of the merchants are lying. He only married one and he only took sechora from one. Should the 4 liars be nischar gain from their lies?
B'kavod,
Sam Kosofsky
Tosfos and other Rishonim ask a version of your question in the beginning of Bava Metzia (3a). The answer they give is that the cases in which Rebbi Akiva says he should pay five times are cases in which we assume that the Mekadesh or the buyer are accountable, since they should have remembered who they stole from, bought from, or married. The Chiyuv to return what is not his in cases like these is stonger than the scare that someone might exploit and utilize the loopholes.
Best Regards,
Aharon Steiner