I wouldn't do it in any Aircraft that required above idle thrust from the running Engine in order to achieve the required duct pressure.
What I said was its ops normal in the 777 or A330 to carryout a cross bleed start during pushback because you don't need more than idle thrust to achieve required minimum duct pressure for a successful start of the other Engine.
If there is any doubt then don't do it during push, either do it before push or after depending on the Tarmac, ATC requirements and ground crew requirements etc etc.
Common sense gentleman.
