This question seems to be of relevance to all business travelers in the EU.
The background of this question is as follows: I work at a university in the EU (Germany). Today there came an email that we need to request a A1 certificate regarding social contributions if we travel to another EU country for any kind of business trip. (I understand that to make the local administration happy, i should fill a form to request this certificate for every EU travel 2 weeks before traveling to another EU country)
This question is however not about my local personal case but about the general case. Do EU residents need an A1 certificate for any business trip in another EU country?
Quick research on the web indicates, that this "strict" interpretation of an EU directive is shared by several German health insurance companies  and large companies like KPMG . Furthermore, their interpretation suggests that this rule applies to all EU citizens who are working in an EU country, and who will go to another EU country for any kind of business trip.
After quick skimming of EU Regulation 987/2009 , to me personally, all of this just seems to make sense for secondments in another university, research center or company. But not for visiting conferences, giving a short talk, or having a short meeting.
Is the interpretation that an A1 certificate is necessary for any small business trip, really correct? How is this handled in Other EU countries? Maybe it is even necessary to distinguish between how this is handled "de jure", and "de facto". What are your experiences, and how are your employers (either companies or universities) dealing with this EU Regulation?
EDIT 1: in a previous version of the question i mistakenly used the term A1 Form, where i should have used A1 certificate or portable document.
EDIT 2: I looked and asked some more: Several big companies in Germany are instructing their employees now to obtain an A1 certificate for their EU business trips(KPMG, Bosch). But since it is about EU rules, it should be a big thing for business travelers, and i am some what surprized that so few people are confronted with this yet. Maybe it is also just some local German interpretation, and many are just coping this interpretation. Here  is an expat website, which also speaks about it in english. Although it seems a complicated matter, i am still interested in experiences and views on this topic.