Gateway send to v2 and v3?

i understand that v2 routes traffic to v3 - but its also possible to set my gateway more then one TTN Endpoint - so its easy to set TTNV2 and TTNv3 in parallel.

This seems to work so far; But i am explicitly unsure weather i should do that or not?

Basicly - the worst thing i actually see is double traffic arriving in v3.