Strange levels of the travel_mechanism variable

[ingonader]

Some levels of the travel_mechanism variable do not make sense, in my opinion. Obviously, more than one travel mechanism might be affected by a single policy (hence the level combinations), but combining additional levels with the "All kinds of transport" category does not seem to be intended. Also combinations of specific levels with "not applicable" might warrant checking the data:

n	travel_mechanism	record_ids
1	All kinds of transport,Buses	2618391Em
1	All kinds of transport,Ferries	2653741NA
9	All kinds of transport,Flights	1894210Br, 3548568NA, 4100633NA, 5844897Ev, 6958285Br, 6948866Em, 6948866Bm, 6948866Ea, 8860389NA
1	All kinds of transport,Flights,Land Border	9438905NA
2	All kinds of transport,Flights,Land Border,Buses	5483285NA, 7760322NA
1	All kinds of transport,Flights,Land Border,Trains,Buses	4276196NA
3	All kinds of transport,Flights,Land Border,Trains,Buses,Seaports,Cruises,Ferries	4414848Ev, 7808990NA, 9098953Ff
4	All kinds of transport,Flights,Land Border,Trains,Buses,Seaports,Cruises,Ferries,Other (please specify)	1961103Em, 1961103De, 9702826Em, 9702826De
2	All kinds of transport,Flights,Other (please specify)	1277241De, 3389029De
3	All kinds of transport,Land Border	3763985NA, 7579852Bm, 7579852De
1	All kinds of transport,Land Border,Trains,Buses,Seaports,Cruises,Ferries	5536379NA
2	All kinds of transport,Not Applicable	2967783NA, 9643209Br
1	All kinds of transport,Other (please specify)	1245058NA
1	All kinds of transport,Seaports	5688595NA
1	Flights,Land Border,Cruises,Not Applicable	6447698Bm
5	Flights,Not Applicable	2416878Br, 3578956NA, 3800316Br, 614367Br, 7115775NA
4	Other (please specify),Not Applicable	407024Ex, 407024Ey, 4175226Em, 7049744NA

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