I will sometimes request a slightly lower reserve so I can get the bidding started. When particularly busy or time limited I have requested a buy now so the deal can be completed.
In cases where the price is nuts I just watchlist the item and wait for the seller to relist with a lower price. They usually do after a couple of relists with no bidders. Pointless messages would probably encourage many of them to hang on longer.
There are many shameless and cringeworthy tryers who message offering very cheeky buy now prices. No doubt they are successful often enough to make the strategy pay. I'm sure there are some that practically do it for a living.
scuwp: Some people get carried away. I have sold some items well above retail price...but hey they bid and won, so their problem. On the other hand I have seen some really good items go for the $1 reserve. That's the gamble you take if you are going to set a low reserve. Personally I would be embarrassed to collect a $500 cellphone for a gold coin donation.
For me I am pedantic about what I buy and research well. I know what I think it's worth and work to that, but yes 50% as a ball park figure is a good start. I use the same rule of thumb for selling based on the days price (not what I paid for it 3 years ago).
Some buyers and sellers are plain unreasonable, but hey I just leave them alone if they are not on planet earth.
Do you think that those $1 reserve auctions that finish at $1 ever get settled or do the people make some excuse not to sell?