From the grapevine:

The pier to casino shuttles are still "free" without any spending proof.

From casino to pier, there are incidences of spending proof, the target is HongKonger who are used to "gaming" the system to get freebie. Grand Lisbon and others in that vicinity are being taken advantage of by the Hong Kong day tourist and they are right to enforce this. I saw people very upset at Grand Lisbon when they were denied boarding in the evening yelling that they were going to miss their ferry.