Until they make all their source code available, I would say yes. Who can create a Ripple node other than them right now? Developing "gateways" for Ripple is like developing Facebook apps; they can shut you down at any moment.
That's not what the word scam means. But yes, be very careful until the code has been released, and make sure that if you use the system, you only use it for small amounts and short periods of time.
In the past week I had a stressful experience with Bitstamp, one of the Ripple gateways, though the problem was not on the Ripple side. Bitstamp is also a Bitcoin exchange and you can use it without using Ripple, just as you might use Mt Gox. I sent some EUR, which took about a day, and which was automatically converted to USD. So in a sense I now held USD IOUs, though not inside the Ripple system.
I could have bought BTC directly on Bitstamp, but since I wanted to support Ripple, I decided to take a detour through it. I withdrew my USD to Ripple, which happened reasonably quickly. I think the delay was due to needing manual clearance from Bitstamp. Now I held Bitstamp-issued USD IOUs in Ripple. Once inside Ripple, I exchanged the USD IOUs for BTC IOUs. This went fast and reasonably smoothly, except for some UI glitches. I then deposited my BTC IOUs into my Bitstamp account, and again, this went reasonably smoothly. I now had BTC being held for me by Bitstamp, outside the Ripple system, just as I would have had if I hadn't made the detour.
When I tried to withdraw my BTC, it again took a short while for the withdrawal to be cleared, but unfortunately it never arrived. It took about 48 hours to resolve this issue, with no feedback from Bitstamp except for an automated acknowledgement of my support ticket. Several other people were having similar problems, and I thought this might be the end for Bitstamp.
In principle, this had nothing to do with Ripple, and the situation was resolved this time, but it does show how risky exchanges and gateways are. 100 EUR was the maximum amount I was willing to risk through Bitstamp and Ripple, and only for a couple of hours, just for immediate conversion to BTC and withdrawal to my own BTC wallet. And right now I'm no longer comfortable with even that.