I know what you mean.
But, the story the LMB owners tell is that these girls are coming over from Portugal where they normally work. As all football fans know, Portugal is the gateway to Europe for Brazilians, so that sells the idea that they are Brazilian rather than bRomanian.
Then they say they come over for a short working visit. Again, it then makes sense that they would work long hours to maximise earnings, as if you had the choice of 4 weeks work in Bury and 4 weeks relaxing in Lisbon or on a Portugese beach, or 4 weeks work in Lisbon and then 4 weeks relaxing by the river in Bury, I think we all know which way around you would do it. I do wonder if they are coming over and saying they are on holiday to customs (not bothered by this personally) and that is why they stay such a short time. And they can probably only come over 2~4 times a year before this starts to look suspicious.
It is a good system, as unlike Raquel who is racking up the positives I would guess most of the foreign WGs who come over give the expected level of service and probably wear out their welcome after a few weeks, but when they come back a few months later, they can get custom again from new punters and those punters with short memories.
I've always wondered if any of the UK WGs in LMB ever go in the opposite direction for a bit of a working holiday, do one day of work one day of holiday for 2 weeks and you've probably paid for the holiday and then some by the end.