Two things may worth noting:
1: Omitting dame play under Japanese rules is legal and an officially endorsed practice.
2: There are good reasons why the rules say no territory and no stone removal in sekis. Counting territory in sekis would of course be broken, but even w/o counting territory, just removing non-alive stones from there is NOT safe theoretically (it could change the cost of some moves into some rare sekis).
Of course servers often simplify things and don’t worry about rare cases (IGS doesn’t even differentiate sekis), but it seems best to lead users to the correct direction - which region is territory (closed off and fully/independently alive) and which isn’t.