This verb, I believe just like the Polish verb, implies regularity (the simple tense is used for this in English).
If I were given your English sentence - Strange people are going to this shop - I would translate that into Russian as Странные люди идут в этот магазин, to indicate the present continuous activity. (Present continuous - they are doing that right now.)
If I wanted to say in general that - Strange people go to this shop - I would say that Странные люди ходят в этот магазин. See the Tips & Notes for Verbs Present 2: https://www.duolingo.com/skill/ru/Verbs-Present-2/tips-and-notes
No, в is followed by either accusative or prepositional. (See table of prepositions here: http://russianlearn.com/grammar/category/table_of_prepositions). So this will be accusative, because we are talking about a direction in which people go -- to this store.
Basically, это = 'this', то = 'that'. However, when there's no contrast between 'this' and 'that', Russian speakers usually only use «этот»/«эта»/«это» and don't use «то», so that's why sometimes «это» is translated 'that'.