It will affect some open order though. Since the OTC match happens against an existing limit order, the quantity of that limit order would reduce based on the trade.
So, by putting an OTC order, you also open an order in the Order book. It's like that, right?
It would look similar to a Market order execution, so yes while some traders may be confused about the reason for the spike (upward or downward), others would probably identify it as a Market order.
The only difference is that the OTC will fulfill against _one_ order instead of _many_ orders like a market order. This is purely a user convenience where they don't mind paying more than LTP to buy, or earning less than LTP to sell - they just want to trade quickly and step away.
Still, it will look strange on the Market charts because it won't affect the previous orders, upwards or downwards. It can be convenient for such users, but on the other hand will be strange to all the others. For me, it looks like a hybrid of a P2P with OTC at the same time, but since it affects the Market becomes very different. I understand the concept, but I don't know if it would be better to do it differently.