It’s a bit disingenuous when folks cry out “Religious Tradition!” about something established by men that offends their non-traditional sensibilities, even if true. It’s like slapping down fake vomit. I can understand why …
Of all the mentions of “traditions” in the Bible, many are unfavorable. But not all of them. For example:
“So then, brethren, stand firm and hold to the traditions which you were taught, whether by word of mouth or by letter from us.” 2 Thessalonians 2:15
and
“Now I praise you because you remember me in everything and hold firmly to the traditions, just as I delivered them to you.” 1 Corinthians 11:2
In both of those cases, tradition is a good thing. In many others cases, i.e. Mark 7:4, Galatians 1:14, Micah 6:16, Mark 7:9, Colossians 2:8 etc., it’s not so good.
One of my favorite obscure passages regarding tradition is this one:
“Do not move the ancient landmark that your fathers have set.” Proverbs 22:28 In principle, it, and its related passages… Deuteronomy 19:14, Deuteronomy 27:17, Job 24:2, and Proverbs 23:10 do not speak directly to tradition, but I think they offer some insight on how to treat tradition’s encroachment on truth. With these thoughts in mind, I have a few questions:
1. When, biblically speaking, must we stand against religious traditions?
2. How, biblically speaking, are we to do that?
3. What, biblically speaking, are religious traditions?
Missionary in the Andes Mountains Cloud Forest Region of Ecuador. My last name, "Labrador," is the word that's used for "Vine Worker" in the Spanish Bible, and it's OK with me. 
William Floyd on 'We Don't Need No Education' ~ The Apostle Paul
I have been greatly assisted in this regard by Os Guinness distinction between “tradition” and “traditionalism”. According to Guinness tradition is “the living faith of the dead” whilst traditionalism is the “dead faith of the living”.
If, by your traditions, you make void the word of God, that is not a good thing.
If, by your traditions, you establish and keep it.. that is a good thing.
It doesn’t seem hard…
But who is willing to look to see what God has said and measure themselves by it?
I think Carolyn’s got it right there. Plain and simple.
To reiterate Miguel’s point I’d say this: Let God be the judge between the two. Why judge other’s traditions unless they are egregiously un-Scriptural? Do what’s right, and let God judge those who do wrong.
You embedded the answer in all three questions…Biblically speaking. I get so annoyed with all the comments that throw up their hands at the idea of deferring to Scripture…to do so is to be tied up in endless wrangling…nothing can be clearly established from Scripture. The same folks abhor ‘religious traditions’ while they are ignorant of the fact that they are walking in the path of one group or another from centuries ago. Wesley’s quadrilateral included tradition as a factor in establishing doctrine and two centuries ago groups went to the mat over whether to only have rules about what is commanded in scripture and condemn the rest or to only condemn what is condemned in Scripture and allow the rest…the whole issue of ‘things indifferent.’
To my way of thinking, we should stand against ‘religious traditions’ that bring people into bondage and legalism…ones that are based on the Old Covenant. I discuss this more on my blog at http://www.revisitingscripture.com.
My personal conviction is that we should stand against religious traditions when they contradict Scripture. God tells us not to worship Him in the way the nations worship their gods (Deuteronomy 12:29-31), and admonishes His people by way of the prophets when they did just that. Jesus said it perfectly in the gospel of Mark:
And answering, He said to them, Well did Isaiah prophesy concerning you, hypocrites; as it has been written: “This people honors Me with the lips, but their heart is far away from Me; and in vain they worship Me, teaching as doctrines the commandments of men.” (Isa. 29:13) For forsaking the commandment of God, you hold the tradition of men: immersings of utensils and cups, and many other such like things you do. And He said to them, Well do you to set aside the commandment of God so that you may keep your tradition. ~Mark 7:6-9
How are we to take a stand against these things? On a personal level, we can simply remove the offending traditions from our lives (easier said than done, right?). Are we then obligated to share our insights with others by taking a more public stand against these traditions? If so, how to do this without causing offense? I wish I had the answer to THOSE questions.