This is one of those jurisdictions that has multiple names. Bonaire, Sint Eustatius and Saba is that used by WIPO and is arguably less ambiguous than the other names used: BES Islands or the Caribbean Netherlands.
The latter demonstrates that it is not an independent part of the Netherlands. It is not even a constituent country of the Kingdom of the Netherlands; note the Kingdom of the Netherlands being different to the Netherlands. They obtained their current status following the dissolution of the Netherlands Antilles on 10 October 2010, that is of special municipalities of the Netherlands. With a collective population of only 21,000, the majority being on Bonaire, this may have been a reason why self-government would have been unattractive.
Many would be forgiven for thinking that now these islands are a part of the Netherlands they would be protected by a trade mark covering the Netherlands (i.e. a Benelux or Community Trade Mark). However, this is not the case and a separate trade mark process is applicable. I use the word "process" here deliberately as a separate Trade Marks Office does not exist. Trade marks are managed through the Benelux Office for Intellectual Property (BOIP) in The Hague, albeit a different section to that administering Benelux trade marks. At least there is a separate website for the part related to Bonaire, Sint Eustatius and Saba: CaribIE.
As you may imagine for a system developed by the BOIP this is an easy on the eye and intuitive website to navigate. Trade mark searches can be conducted on-line and an on-line filing facility exists. According to the guidance notes, it appears that if you are the proprietor filing directly then you do not need an agent but if you appoint one then they must have an address in either Aruba, Curaçao, the Netherlands, Sint Maarten or, naturally, Bonaire, Sint Eustatius or Saba. In practice, most are based in Curaçao, given this is where the Netherlands Antilles' IP Office was, or in the Netherlands. Representatives from Belgium or Luxembourg or other EEA states are not accorded representative rights currently (as they are for the BOIP in Benelux trade mark matters).
It is possible to file trade mark applications in English in addition to Dutch. English has official status on Sint Eustatius and Saba. It is not currently possible to file in Papiamentu which is co-official with Dutch in Bonaire (see also under Aruba).
If you did not confirm old Netherlands Antilles registrations with the CaribIE then the deadline in which to do so has now passed.
The Madrid Protocol has been extended to Bonaire, Sint Eustatius and Saba by the Dutch government but a designation must be requested separately from that of the Benelux or European Community and separate fees must be paid.
Older International Registrations that designated the Netherlands Antilles will have continued to have effect in Bonaire, Sint Eustatius and Saba automatically.
I am not aware that it is possible to register Industrial Designs in Bonaire, Sint Eustatius and Saba. In view of its special status within the Netherlands, I would doubt that Benelux (or indeed Community) Designs provide protection. International Hague System registration has not been available since the freeze of the London Act (applicable to Bonaire, Sint Eustatius and Saba) on 1 January 2010 and an official denunciation of this was made by the Dutch Government on 13 December 2010.
In October 2015, the special status of Bonaire, Sint Eustatius and Saba will be reviewed by the Dutch Government and the islands could be included within the European Union (there are provisions in the Lisbon Agreement to do so). Logistically this may not be desirable for obvious geographic reasons and the islands use the US dollar as their currency, not the Euro.
If the islands do become a part of the European Union then Community Trade Marks and Registered Community Designs would be expected to be automatically extended. However, would it, for example, be possible to file opposition to a Community Trade Mark based on a Bonaire, Sint Eustatius and Saba registration? I would doubt it because OHIM considers Gibraltar a part of the European Union yet basing an opposition on a Gibraltarian registration is not possible (at least not on the opposition form). (This is almost nitpicking as to have a registration in Gibraltar requires one in the United Kingdom; although a CTM opponent could conceivably prefer to base an opposition on a registration in Gibraltar as opposed to the UK to avoid a possible counter-claim to its mark in a larger market.)
To avoid going off at a tangent (bit late!) and back to Bonaire, Sint Eustatius and Saba where many will anticipate little change to its current relationship with the EU. We may not have to worry ourselves about such a scenario.