4 segments maximum for baggage tags is the same as the 4 segment maximum for an airline ticket. this is a legacy of the old paper tickets, which came in booklets of 4 coupons. It should be routine (albeit rare) to generate 2 baggage tags for a 4+ segment on-line (same airline) itinerary, but it might be much more complicated if not impossible to interline, based on the different systems the airlines might be working with.