Most EU expats living in the Netherlands have dealt with the constant problem of many services or businesses asking for the renown IND sticker to be present on their passports in order to gain access to said services or businesses.
So far many Dutch businesses and services where demanding for the sticker even with EU residents. Personal examples are Zilveren Kruis, which after email contact failed to site the law (3 times) that requires an EU citizen to have the sticker on his passport in order to get medical insurance and T-Mobile, who forced quite a lot of people to go and get the sticker in order to have access to their services.
Besides those personal notices on the two mentioned companies there have been several reports of EU citizens being asked the same thing from various other businesses and organisations in order to prove their residency status the previous year.
Since January 6th 2014, the requirement for the IND sticker is no longer valid for EU citizens and you can just show your (valid) passport or ID in order to provide lawful proof or residency.
You can see more here at the English version of the announcement by the IND.
Feel free also to download a letter (in Dutch) from the IND that you can show to companies and organisations in case they need proof of legal residency.