27 CFR §6.94

An industry member may give or sponsor educational seminars for employees of retailers either at the industry member's premises or at the retail establishment. Examples would be seminars dealing with use of a retailer's equipment, training seminars for employees of retailers, or tours of industry member's plant premises. This section does not authorize an industry member to pay a retailer's expense in conjunction with an educational seminar (such as travel and lodging). This does not preclude providing nominal hospitality during the event.