My in-law's house is being remodeled due to a plumbing issue and their insurance company is putting them up in a hotel (Residence Inn) while the remodel is in process. By the time we're done it will be a little over 60 nights in the hotel. Since they don't care about the miles and points world (and I do!), I went with them over the weekend to add my name as a second guest and also added my Marriott number so I can hopefully get the nights credited to my account. Front desk said the number was added successfully but who knows what will actually happen in the end. The charges are all being master billed to the insurance company so no double dip opportunity here by also offering to pay on my SPG Amex/get reimbursed.

That said, has anybody had experience adding a loyalty number mid-reservation as a second guest and having the stay/night credits post successfully? I'm doubtful any points will credit since it's a master bill/negotiated long-term stay rate situation. FWIW I don't see any updates in my Marriott account for the current stay or anything to indicate I'm "staying" at that hotel. Therefore I'm not sure if everything will correctly post upon checkout in a few weeks. Also, I don't know if all the IT issues surrounding the merger are impacting/will impact our situation either.

Any thoughts or prior experience in a situation like this?