I have had some brilliant offers made by buyers seeking to purchase several items from me at once, so I am happy to receive offers - I ignore those that are ridiculously low (which is one or two a year across IDs) and consider all others (which is at least one every other week on all IDs). 

The buyers making the offers are not seeking to trade off ebay, so how the offers to buy or sell outside eBay policy would even apply in this situation is unclear to me.