Post-it notes on a tech log...............Oh for crying out loud.
It is not acceptable. The systems must be robust enough to inform people about any defects that an aircraft is carrying.
Defects can be deferred until it is sensible to repair them. Operating restrictions might need to be put in place, but that isn't too hard.
You are PIC and it is well within your right to ground any aircraft you see fit to do so. If you get a row over it, then stand your ground. You are in the right. Whilst I have had many people ground things for no reason, you have to manage that and be able to defer the defect as needed.
A bit of commonsense is required, for example grounding an aircraft because an instrument light has gone out is a pain, but all that needs to happen is that the defect is deferred until it can be fixed, with a restriction such as "no night flying."
I once got into an aircraft that was loaded and fuelled and found a note on the throttle quadrant from the fleet manager.
"Took 5 attempts to lower gear on first sector, 3 attempts on the second sector.
Keep the show on the road and the engineers will look at it tomorrow."
Strangely enough, the first action was to unload the aircraft and then ring up the fleet manager and inform him that he was an f'in idiot if he thought we'd be taking that aircraft anywhere.
My 3rd action was to get out of that company as soon as possible.
Techlogs are there for a reason, use them properly. End of.