Make no mistake about it, there are / were still numerous positions from SDPOS to Toolpushers to OIMs being filled by foreigners (Brits, Scots, etc.) on TOI assets in the GOM. I can't say for sure that goes on at Sea Drill, Noble, or Diamond in the GOM, but it would not surprise me. Those manning cert waivers for those specific positions / personnel (as somebody said prior) were prominently displayed on the bridge deck p'way bulkheads along with flag state certs, etc on the TOI driller I was working on.
I think the reason that Stena, Maersk, and Vantage get away with all the foreigners they have aboard (no excuse for it being allowed)is because they have / had so few vessels here compared to those other 4 companies. Ultimately, they are filing waivers for a few people on one or maybe 2 vessels. It still sucks, but nothing new there.
An LDO friend of mine at Vantage tells me appalling stories about all the foreigners (RSA, Brazil, Croatia) working as LDOs in the GOM. And some of them are very recent placements (last 6 mos) in ADPO roles.
Another issue (IMHO) is that so many of these companies (sub sea construction, IMR, DSVs, etc.) write up outlandish pre-requisites for work experience (equipment specific, 1000s of hrs experience, etc., etc.) that they use (heavy-handed) to deny applicants. And it really doesn't matter how or why, b/c the USCG or DOL could give 2 shits anyway.
I recently turned down an offer of cargo supv (2/M) on an FPSO working for Shell/SBM in the GOM on a very long term contract. It wasn't great wages, but it was guaranteed, long-term work in an imploding market. One deciding factor in declining the offer was because I had zero faith in the employer telling me that that after one year in the GOM, the manning waivers would expire for the C/M and Capt. I have no doubts that if a company like SBM, let alone Shell, want continued waivers for those positions (and others), the USCG will not bat an eye at their extension requests.