In Hamburg there is a very conservative local political party that always take a few districts in the "First Vote" and gets 2 or 3 members of parliament. But "Second Votes" for this party would be wasted conservative votes.
I think it is good news that the 49:48 polling does not add up to 100%, meaning that nonsense parties like the NPD (Neonazis) and the true communist parties are cluttering up the remaining 3% of the polling but will NOT count at all on Sunday's final results because of the 5% rule that each party has to have to win any seats at all (unless one of their people gets directly elected somewhere).
So 49:48, really means 51.5:49.5 in favor of the conservatives. Mathematically, you MUST make this calculation. The problem is: that is too close with 25% of the population undecided.
What if they are only undecided between the Greens and the Linkspartei? That is a big thing to fear. The undecideds could easily be mostly lefties wondering whether to be loyal or radical.
But something good to fear is in play as well. If the undecideds are all wondering if they will vote for the Greens or the Linkspartei (commies), then the CDU wins the direct vote in almost every district of the country (the left having split itself into 3 groups). The SPD can only win a lot of direct elections in individual districts (first votes) if undecideds in that district decide to be loyal to the SPD in order to keep the CDU from winning by default the way Clinton beat Bush in 1992 because of Perot.
I think the preliminary results (Hochrechnungen) start coming in around 8PM German time on Sunday.
Undecideds usually break at the end against the incumbent party, so the CDU and FDP are most likely to gain, but Linke might gain some disaffacted SPD/Green voters.