I would assume that when RBC and others do their channel checks the numbers are low-balled by the wise casino managers to prevent the analyst from over hyping their expectations. Therefore, when LVS reports numbers that are equal to~ 20% it is probably on the low side. ??????
Generally, channel checks use multiple sources to confirm data. Casino managers are just one of them.
A month or so ago, I cited an example from the coal industry, where a channel check involved querying Chinese ports on coal imports. To confirm what they got, they also employed a person to sit on a hilltop overlooking the shipping channel to count the number and size of ships entering the harbor.