Detailed Explanation
Sour Mik invokes the following laws.
We discussed in Issue 138 that upon the consumer's discovery of a defect, the consumer would generally have to prove that the defective article was defective prior to the moment of purchase, before Beit Din can compel the seller to anull the sale. In other words, we will respect the status quo of the money as the halacha says:
When the plaintiff is rationally convinced of his/her claim, we apply the following theorem:
1. "The onus of proof lies upon the party interested in altering the fund's status quo" [Bava Kama 46, Shev Shmatza 2].
Consequently, if the consumer already paid for the merchandise, the onus of proof would lie upon the consumer. If the consumer had yet to pay for the merchandise, the onus of proof would lie upon the merchant.
However, in Sour Milk, Emily may lack proof that the milk spoiled before she bought it. Similarly, she may lack proof that she did not receive a magazine.
Is there recourse for a plaintiff who hnows he/she is right but lacks the ability in Beis Din to retrieve her money?
Yes. The plaintiff can often alter the status quo of the money.
By what means?
2. With the exception of forcefully taking a collateral for an outstanding loan which is a biblical prohibition to do so; [Choshen Mishpat 97:6] a plaintiff who is certain about his/her claim may grab the defendant's article provided that by doing so, the plaintiff can prevail in Beit Din [Choshen Mishpat 4: 1].
Once the article is in Emily's domain, she can prevail in Beit Din by compelling the other party to prove that she is wrong and that she did not purchase the article. Her right to grab the article(s) are due to the fact that were the articles in her domain, Beit Din would award them to her anyway.
Consequently, Emily may not grab the articles/merchandise in front of two witnesses.
Why not?
If two witnesses testify that they saw her grabbing an article from the defendant, Beit Din must deal with her as though she were a thief even if she claims she toook the articles rightfuly.
Two more considerations must be weighed before deciding to grab the due merchandise in front of people (or a closed circuit TV - for that matter).
3. It is forbidden to behave in a manner by which people will view you as a thief or sinner [Bamidbar 32: 22, ].
4. It is absolutely forbidden to behave in a manner which will cause others to have disrespect towards Hashem, His Torah, and assosciate dishonesty with Jews. The Heavenly punishment for such behavior is grave [Maseches Yoma 86a].
Application
Emily may take $3.00 worth of merchandise and a fresh milk if she is certain that the milk spoiled before she left the store. Emily may not do so if people will misunderstand her behavior as shoplifting. Emily may not do so in front of two people who can testify in Beit Din that she took merchandise from the store without paying as she no longer will prevail in Court.