I believe the vote from more elderly citizens could be decisive, they do not show as much of a presence on discussion forums, nor do they tend to be as vocal publicly as the younger members of society, yet if that survey has any merit at all, it suggests that a lot of them will vote to leave.
As an aside there was an interesting news article this morning in the Romanian press, although it nothing more than we already knew, many if not most of the migrants/asylum seekers aren't so interested in anything other than getting to a wealthier Eu member country suggesting they are indeed economic migrants :-
"Half of the refugees who were supposed to be moved from Greece to Romania withdrew from the relocation program and disappeared. Most of the refugees allocated to Bulgaria have also fled, according to sources familiar with the situation quoted by Financial Times.
Some 191 of the 1,324 refugees (one in seven) who were already supposed to be relocated from Greece to other EU countries have left the program and disappeared.
The European Commission decided, in October 2015, to relocate 160,000 refugees from Greece and Italy to other EU countries, based on mandatory quotas. Romania, the Czech Republic, Slovakian, and Hungary voted against this measure, but had to accept it as all the other countries voted for.
Most Romanians oppose refugees settling into the country and it seems that the refugees are not interested in coming to Romania, one of the EU’s poorest countries, either. According to official data announced by the Greek authorities, 32 out of the 67 asylum seekers who were supposed to be transferred to Romania already refused to come.
Similarly, 36 of the 47 refugees that were supposed to get to Bulgaria also left the program."