Do We Need to Always Share the Gospel?

I was talking to a good friend the other day and she was telling me about a situation she had where a couple of Russian exchange students approached her as she sat by the beach. They had a decent conversation, talking about America, her life, what they were doing here. The Gospel itself never came up. Jesus was mentioned as she talked about who she was. The fact that He is the only way to heaven was not brought up though.

We joked a little that I couldn't believe a Bible college student didn't bring up the Gospel in that situation. We were on the same page, however, when thinking about evangelism as part of discipleship, as part of a relationship, pointing the other person closer to the Cross of Christ in that relational context. The question was raised then, should it be different when speaking to someone that you know you'll never see again?

What about the times when a relationship really can't be built? Do we go back to our "confrontational" methods of evangelism or do we mention Jesus in passing and pray that they run into someone they can build a relationship with that will point them to the Cross of Christ? Or is it something else entirely?

I have some answers but I thought this would be a good subject to raise to both anyone who would like to comment or any of the other "bloggers" connected The Couch who would want to post their responses. Kind of an interaction collaboration. :)

So, here's the question more clearly: When we don't have time to build a relationship with someone, do we need to feel compelled to always share the Gospel with those who do not know Christ?