Gurudevanrupantike - Guru, God and King are here mentioned but one should include the Vrudh, Tyagi, Vidhvaan and Tapasvi as previously mentioned.
One should not sit in the said manner, as it is discourteous and disrespectful. Shatanand clarifies that one leg upon the other thigh is prohibited here and not both legs upon opposite thighs (as this is a form of Yogasan).
Similarly one should not sit in a stropy manner with legs outstretched etc. as this also displays disrespect. Thus one should assume a posture of sitting with the legs crossed with the back straight (mind you, not too straight, so as to look proud or egotistical!)