just a couple thoughts..

I liked ma'am 's reply to the thread.

a sub who chooses to test a her Dominant ... so much of that I dissapprove of. Is a bad thing to do in a rt relationship.
wonders why it is necessary in online?

on the stopping a task or failure to complete.. everyone is correct.. tell the Dominant. Be open and honest as to why.
Do not test to see what the Dom will do.

And because you know you tested him and that he may be mad.. .you should equally be ready to receive his punishment knowing one deserves the other.