In at least the US and UK lots of items that are sold in multipacks come with a notice on them that often reads:
Not for individual resale
That always strikes me as slightly odd - it looks like it's intended to be a contractual term that I can only see after opening the outer packaging and in a situation where I wouldn't expect any terms to apply other than between myself and the retailer/wholesaler.
If I were to choose to ignore that and split multipacks to sell them later would the manufacturer of the product in question have any recourse against me? (In either of the aforementioned jurisdictions)