@Isaac93, I can understand that you may feel this is a future opportunity, and some hosts may like it. However I am the type of host who is looking to reduce my use of single use items and in particular excessive packaging.
Using refill containers works best for me. I buy products in advance when they are onsale and top up guest supplies as required. The rate of usage by guests is fairly unpredictable, so top ups and refills are economic financially, they take up less storage space, produce less landfill, and are more effient recycling.
Also having more than one type of product allows guests to choose the product that best suits their skin and hair etc. If they squirt a bit extra into their own mini travel containers, I don't care. It's no big deal if they leave happier and with a bit of extra shampoo in case they need it for their next venue.
Best regards
Christine