I believe it is true that we must be careful how we influence others. But there is a ditch on both sides of the road. For, me, the most dangerous thing there is in regards to the word is requiring something of someone FOR salvation that God does NOT require. I personally believe that is heresy of the worst kind.
There is nothing wrong with personal convictions. We all have them and we all have standards in our lives which we live by. But the real danger is requiring something of God's people that He does not require. I have absolutely no problem whatsoever with an Ultra-Con living out an Ultra-Con lifestyle. More power to them!!! But when they state that it is required for salvation, then I have a problem with it. I fully and completely respect someone with "strict" standards. But when they try to state that I MUST do the same or I am going to hell, then I have a real problem with that, and I believe God does as well.
When we tell people that unless they speak with tongues, they are going to hell, I believe that grieves the heart of God. Speaking in tongues is a biblical experience promised to ALL, but when we state that we have to flap our lips to escape the flames of hell, I believe that is heresy.
So, yes, we must be careful, but we also need to be careful about what we're careful about!