This is a really annoying feature with the select and scale tools.
When a tool is not active, pressing the tool's hotkey activates the tool. However, if the tool was already active, pressing its hotkey cycles to the next variant of that tool (e.g. rectangular select tool becomes circular select tool).
As general habit, when a user needs to use a tool, they press the tool's hotkey and then use the tool. They don't check first whether the tool is active, which would require looking up and locating the tool's button among a sea of other buttons. It's quicker to simply press the hotkey.
This means that if the tool was already active, suddenly you've used the wrong tool and have to undo and then select the right tool (which either means cycling back through to the start, or having to click the tool manually). It's often very easy to not realise a tool is already active, for example when the transformation gizmo is not on the screen, and often the mouse icon doesn't update to that of the active tool. Basically, this happens often, which gets very frustrating. It would be so much simpler to just click a key a know I have the tool I want.
In Adobe, cycling trough a tool's variants is achieved by pressing the tool's hotkey plus a modifier key, which is perfectly intuitive, and very hard to do by accident. I suggest the same approach be taken in Max.
