So if i come here and say im going to launch a lottery, 0.01 each ticket, if you get lucky you might win 1 bitcoin but im not going to tell you the odds and it is not certain if anyone will win. Thats not a scam to you because i stated clearly how it works?
Well, I don't think anyone would give you any money in that case. The same should be true of a ponzi that acts similar. If you actually read any ponzi schemes, they tend to have payout amounts, dates, etc. The odds are dynamic, not unknown.
In your situation, no I don't think its a scam, unless you intend on scamming in the first place. People are welcome to throw away their money if they want. Its their decision.