When is a hesitation not a hesitation?
1) Partner makes a stop bid and correctly displays the stop card. However, unfortunately as is very common at many clubs, RHO bids almost immediately and partner removes the stop card. You have a difficult choice of call (perhaps whether to pass or raise to game). Are you entitled to think for (say) up to 14 or 15 seconds (10 for the disregarded stop plus 4 or so for normal reflection) before calling without the risk of being accused of imparting UI to partner who might wish to take further action in the auction?
When the stop card is disregarded in this way, should the stop bidder instead leave the stop card on the table for the full ten seconds during which time their partner should pause before calling?
2) Suppose partner faces their opening lead, dummy goes down and declarer almost immediately calls for a card from dummy. You happen to have a singleton in the suit led, but want to inspect dummy and plan the killing defence . Are you justified in pausing before playing your singleton? Some people suggest placing the card face down on the table and then pause to peruse dummy before revealing your play. However, this seems to risk giving UI either to partner or declarer that you have a singleton or at least nothing to think about regarding the card played.
3) Suppose after a few tricks to a hand have been played, declarer leads a card in a suit in which you now have a singleton. However, you are on 'autopilot' towards the end of a long session and fail to notice declarer's play (perhaps on the previous trick declarer ruffed or overtook dummy's card unexpectedly or you were simply thinking about a pint in the pub afterwards ). After a substantial pause you wake up.
Should you make a comment to the effect: "sorry I was dreaming" or "I thought dummy/partner was on lead" so that it is later clear that you were not pausing with a singleton to mislead declarer? Or do such comments make the situation worse by perhaps imparting UI to partner?