An obligation to use cash register systems that meet the requirements in the Cash Register System Act and Regulations apply to enterprises with a bookkeeping obligation that have cash sales ref. the Bookkeeping Act section 10a (comes to force the 1st of January 2019).
Cash sales are defined in the Cash Register System Act section 2 letter a:
"cash sales: sales of goods and services in which the purchaser’s payment obligation to the vendor is settled on delivery by the use of a payment card or cash as a means of payment. Internet sales and cash on delivery sales are not to be regarded as cash sales,"
Hotels will regularly have cash sales by this definition and are obliged to use a cash register system according to the Cash Register System Act to document cash sales. Order/booking systems etc. are not included in the new cash register legislation but when they are integrated systems in the cash register system, these must shortly be described in the system documentation ref. the Cash Register System Act section 3 (2).