Was that complete coincidence or did they come from the same direction?

Complete coincidence, different directions (AFAIK)

Apparently there is a fairly large one that currently has a 1% chance of a hit in 2048.

Do you have a link ?

Have you ever looked up the chance that an average person is involved in a deadly accident the coming 35 years?

The odds of a hit in a populated area are low, but I doubt NASA can give strike positions accurate enough to be really meaningful.

IIRC only 5% of the land is populated. so chances are indeed low (but you never know)

To get a feeling of the distances/timing about strike positions some simple (rounded) math.

The earth rotates around the sun.

Distance 150.000.000 km.

So the orbit is 1.000.000.000 km (2*PI*distance)

That distance is done in a year = 365 x 24 x 60 x 60 seconds = 31.536.000 seconds

So the earth moves about 31.7 km/sec in its orbit. (mind you that is ~3x faster than it rotates at the equator. ~93x speed of sound)

The earth has a diameter of ~13000 km

That means after ~7 minutes the earth is moved one earth diameter in its orbit.

So the difference between a full hit and a full miss is about 3.5 minutes.

That means you need to have the trajectory exact up to that order of magnitude to know for sure.

suppose you detect a big stone flying 5000 km per hour +- 0.1% (so accurate on 5 km per hour, that's pretty accurate)

suppose the stone is heading earth and it is detected while it has the same distance as the moon 385.000 km (pretty close)

Then it will take between ~4615 and ~4625 minutes before it reaches earth.

the difference of 10 minutes is enough to move the earth 1.5 earth diameter

==> so even a 0.1% speed accuracy is not enough to be sure about the hit when detected at moon distance.

Maybe they could say an asteroid will hit the East coast of USA and the blast might be 2M tonnes, but is that helpful?

Depends on when they can tell, besides evacuating the target area (which might be impossible) one could at least evacuate the coast of Europe as there might be a tsunami (squared)

It seems there may be loads of entire planets cannon balling through space but again the chances of getting hit are slim.

But they have an eternity to do so...