When is a kitchen kosher?

Question

We are moving to a new community and we will be facing the following dilemma:

If/when we get invited for a meal (Shabbos dinner, etc.) how do I determine if the house is kosher?

When we started keeping kosher we got asked number of questions to determine that our house is kosher (I wish I remembered). But also people that knew us would endure long questions about halachot of kashrut so they knew we were not doing it kosher-style.

I am not talking about chumrot like chalav israel or particular schita, I am talking about much more basic level do they know and follow the basic halachot.

One approach is to dan everybody l'kaf zechut and accept all invitations until you learn about violation. The other approach is to decline all invitations - this is the approach of all Chabad families that I know.

I don't want this to be a discussion on how not to offend a fellow Jew which is important issue by itself. I would like this to be more halachic discussion of what makes a house kosher.

For example -

1. if you didn't tovel keilim - not sure, i think solid ok, liquid not ok
2. how you check your vegetables - i think not as long there is some check
3. which hechsherim you accept - as long they are on the list
4. where you go if you have question

One last point, an Ashkenazi can eat in Sefaradi house on Pesach from a pot where rice was cooked see this question. So in many cases you can follow different minhag outside of the house. So again what makes a house kosher on a very basic level.

Would love to hear your opinions

Answer 1

A solution that works for me is to ask the local Rabbi discreetly as to whether you can trust this person and eat by them.

Answer 2

I was taught that you can rely on the word of a (presumably adult) Jew who is shomer mitzvos -- practically defined as being shomer Shabbos (especially shomer Shabbos) and shomer kashrus -- that their kitchen and the food they give you is kosher.

However, like @Shokhet, I don't necessarily agree with your last point, either theoretically (that one may eat things excluded by one's regular minhag if one is outside the home) or specifically (that eating from a pot used for kitniyos would be a problem in the home of an Ashenazi).

That said, I have heard of some distinctly lenient, I think nonmainstream opinions that allow using the non-kosher plates and even eating food prepared in the non-kosher pots of a non-kosher home that is not your own, perhaps because of something to do with stam keilim eino b'nei yomo. This lends some support to your assertion that "in many cases you can follow different minhag outside of the house." It is also correct, as far as I know, that your host's dishes do not have to be toiveled in order for you to be able to eat their food.