I will also look at other trees, but that's because Ancestry will keep throwing out hints, sometimes quite ridiculous ones.
If my Mary lived all her life in the UK I cannot understand why Mary, born and died in the US has any connection at all. so those I tell Ancestry to ignore. If, however, there is a tree seeming to match the relevant details I take a look, hoping to find a new researcher to contact.
Sometimes the trees are public so I can take a look to see if this is really the same person, but often they are private, which is fine, I understand some of the reasoning behind that option.
It is so very easy to send a message to the owner of both types of tree, and patiently await a response. Sometimes they come, sometimes not.
If one absolutely knows that there is a blatant error on another person's tree why not advise them of it? I would welcome the knowledge. Similarly, if some information is found about a particular person which has eluded discovery for some time I would be overjoyed and pass on my thanks.