That brand is problem-free straight out of the factory.
well unfortunately in real world this is likely a situation that sometime do not materialize even with the most expensive and premium of price and brand . Try not to get over hyped about this tough, most pens mentioned thus had been well received and generally they are all delivered in working condition, I would say the possibility of getting a lemon is no more or no less than like of most consumer product, which mean they chance is fairly low but its not zero. Most of the brand mentioned would happily exchange you a new one if you bought one new and it come out defective. Of course Fountain Pen had particulars that's its own, and generally if you treat it with its usage and need in mind everything would be fine. In these days of everyone so accustomed to the convenience of modern consumer product and their related culture its all too easy to forget the basics, by that I mean basics like tools need maintenance / cleaning and this is no more apparent in a fountain pen.
Late to the thread but I certainly agree with most mentioned prior, and of course as others puts it, the best way to not t lost a cap is not to have one at all, but Pilot Capless had its own issue and not exactly inexpensive either. Moonman, Deike, PenBBS, Wing Sung, and a few other more up to date Chinese release are top contender for the job, Pilot 78G is a good pen but its also lightly build unfortunately. if its just robustness, and ease of use .. I would recommend Platinum Plaisir, even though its a sap cap its got one of the best sealing system to keep the nib wet and ready. However my choice for a screw cap inexpensive pen would likely be a PenBBS or Moonman/Delike model with their ( bent ) petite calligraphy nib. The New Moon series in particular serves, from the petite original NM, to the slightly larger NM2 to the heavy and heavily build metal NM3 and this brings in the other aspect of consideration, size, profile, weight .. screw cap and Medium nib is features but had little to do with how the pen actually feel in the hand , how it hold and how it feel. Your cousin may or may not like a wide girth pen as oppose to a thin pen , and he may or may not like the weight.