Q. What if I’m invited to someones house and I’m not sure if they toveled their dishes, can you eat there?
Thank you. Have a nice day and Shabbat Shalom.

A. In general people who are considered Torah observant maintain a chazaka ok kashrus, meaning that we may assume that they practice all mitzvos in a proper fashion, unless we know otherwise.
In this particular case, even if you became aware that the utensils were not immersed in a mikva,

Horav Shlomo Miller’s Shlit”a opinion is that in need you may still eat on that venue, since the obligation of tevilas kelim rests on the owner of the utensils and not on the user. This is similar to the permitted entering into someones house that does not have mezuzos installed. The responsibility of placing mezuzos lays on the owner.

Rabbi A. Bartfeld as revised by Horav Shlomo Miller Shlit”a