HD, far better to take the occasional unnecessary bit of avoiding action than to have something far worse because Mode C was switched off so no safety nets to stop worst case scenario.
Don't take this the wrong way but you've been gone a while now and things have moved on. For example, leaving aside the ACAS benefits, there's new kit being introduced early next year that will warn of infringements automatically but it relies on both Mode A and C (or S) being switched on to work to maximum benefit. So, to any pilots reading, if you have A and C (or S) please switch them on at all times unless specifically requested by ATC to switch them off.