I am on the worship team at my church, and, well, I don't feel like I've completely worshiped until/unless there has been some spontaneous worship or a song of the Lord goes forth, whether I'm the one who "steps out" or not. From my observation, people seem a little bit uncomfortable with this hapening when they first encounter it, but after several times, they seem to get the idea. I really enjoy it a lot when there are a lot of voices being raised up at the same time, singing to the Lord from worshiping hearts, but that is only occasional - I think it should happen more often.
Actually, there is a Hebrew word for spontaneous praise - tehillah - and this is the word used in that verse that says that God inhabits the praises of His people - these praises are spontaneous praises from the heart.....
Ps 34:1
1 I will bless the LORD at all times; his tehillah shall continually be in my mouth.
Ps 40:3
3 He has put a new song in my mouth-- tehillah to our God; many will see it and fear, and will trust in the LORD.
Ps 100:4
4 Enter into His gates with thanksgiving, and into His courts with praise. Be thankful to Him, and bless His name.
Isa 61:3
3 To console those who mourn in Zion, to give them beauty for ashes, the oil of joy for mourning, the garment of tehillah for the spirit of heaviness; that they may be called trees of righteousness, the planting of the LORD, that He may be glorified."
blessings
talitha