Yes, it is true that eyewitness testimony is not always reliable. This has been demonstrated time and time again. We should never be naive and gullible in believing that what everybody says or claims is automatically true.
We have to consider their character, their credibility, their competency, their confirmability etcetera.
There are people who often question the competency of the resurrection eyewitnesses based on the fact that there are many cases of people who witnessed a robbery for example who could not be relied upon as to their testimonies of what really happened. It happened so fast that they are not competent as witnesses to what happened.
But the eyewitnesses we have for the resurrection were not witnesses that witnessed an event that occurred in flash as in a drive-by shooting or witnessed an event that happened in minutes. No, what they witnessed happened for more than a month with many infallible proofs. They had ample and sufficient time to evaluate, assess, examine, confirm or even disprove the resurrected Christ before them. Some of them did not even believe even though the evidence was right in front of them; eating, speaking, walking with them.
Mt 28:16 Then the eleven disciples went away into Galilee, to the mountain which Jesus had appointed for them.17 When they saw Him, they worshiped Him; but some doubted.
What overcame their doubtful disposition? The stubborn fact.
* One of them, a doubter, Thomas by name, even handled Him. He was practically told to "examine Me yourself Thomas!"
Joh 20:27 Then He said to Thomas, "Reach your finger here, and look at My hands; and reach your hand here, and put it into My side. Do not be unbelieving, but believing."
* In fact, all of them were invited to examine Him!
Lu 24:39 "Behold My hands and My feet, that it is I Myself. HANDLE ME and see, for a spirit does not have flesh and bones as you see I have."
* They had a wide window of opportunity to examine Him!
Ac 1:3 to whom He also presented Himself alive after His suffering by many infallible proofs, being seen by them during FORTY DAYS and speaking of the things pertaining to the kingdom of God.
To compare the quality of witnesses in a drive-by shooting or a robbery that happened within minutes to the quality of the witnesses we have for the resurrection is to compare apples and oranges.
