Is it ethical to use another university's journal subscription if yours doesn't have access?
Is it against the law? Probably.

It it scientific misconduct? A breach of ethics? Hardly.

It is acceptable? It's your decision to make based on risk analysis. If you don't do it on a large scale (i.e. someone supplying many people with papers), it's probably okay. It is common practice.



Also, be aware that many journal articles can now be found either in pre-print or post-print form online (though this depends widely on your field), either on institutional repositories or on the authors' webpages. If you're merely missing access every once in a while, you can also nicely ask the corresponding author.