I agree with your employees. In addition, declining gifts may be taken as an insult, especially when dealing with foreign clients from countries where modest gifting is part of the business culture. I’d suggest instead that you allow them subject to specific limitations following the HRI Model Gifts Policy, https://hrinsider.ca/tool-model-gifts-acceptance-policy/
As for the so called “de minimus” threshold, there is no legally required dollar. Our Model Policy uses $100, which is consistent with standards followed in many corporations. There should also be aggregate limits and bans on accepting certain types of gifts, like cash or financial instruments. Again, check out the Model Policy. Also consider whether to require employees to report the gifts they receive, even the de minimis ones. Hope that helps. Glenn