No, but they can by mutual agreement with Marriott corporate (aka by plan). When they initially added RC earning capability to MR program certain properties were excluded including RC Singapore as noted in MR T&C. Also excluded are RCs which cannot be found on the RC web site (like CHI RC [Four Seasons] mentioned by previous poster) and those exceptions noted in 11. a. and 11. o. in the MR T&C.

Yes, see 11. a. and 11. o. in the MR T&C for those that do not participate. The remaining RCs found on www.ritz-carlton.com do participate.