Now you see it. Now you don't.

Instant churches (it's mostly churches) are popping up in public schools every weekend and vanishing within hours of the benediction. I wrote about the trend in today's cover story and co-worker Natalie DiBlasio found several examples of convenience -- and conflicts -- that come with the instant church phenomenon.

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While most schools, mindful of constitutional restrictions on the entanglement of church and state, take a strictly hand's off approach. The pop-up prayer sessions can do nothing permanent to the facilities and in most places may not advertise their presence to the general public.

But Linda Streeter, director of community education for the Dysart Unified School District in Phoenix suburb of Surprise, Ariz., one of the nation's fastest growing districts, allows religious groups to advertise their locale with prior approval and lets them set up a portable baptistery on the lawn.

Pastor Jesse Eisenhart of the 5-year-old True North Church, currently meeting in a middle school gym in Mantua, N.J., says the space has allowed their congregation to double from 250 to 500 worshipers. He says they have met the decor challenges with "creativity," but they also spent $1,000 to install ceiling motors to raise and lower sound speakers -- a permanent installation permitted because it benefits the school.

That's not allowed in New York City, where the board made one school take down a satellite dish it installed without permission.

Rev. Michael Prewitt, now serving as pastor of Calvin Presbyterian Church in Cumberland, R.I., tells DiBlasio about years of church-in-school experiences that he said, "make you feel like a missionary in your own back yard in America" and really bound volunteers to a sense of community.

Still, it could be funny at times. Prewitt says,

We got accused one time of not erasing the wipe-board well enough and leaving 'faint spiritual messages' so that has become a joke among us. Maybe we didn't erase the word Jesus quite enough.

Would it worry you -- or delight you -- if your child came to school and found Jesus' name faintly inscribed on the blackboard? Do you worship in an "instant church" at a school setting?

See photos of: Jesus