just getting back to playing from 1999

i think back then multiple accounts could be a problem. Is that still an issue? how is it made better if someone can make like 10 accounts and just totally destroy a country of anyone who attacks them for example?

the same kind of question goes for bots. like bots could probably do this even more efficiantly now, before bots were so good people would at least have to spend all their time taking the turns of each multiple account.

thanks.