Do bear in mind that part of that may not be pre-emptive about doping scandals, but simply that they perceive it isn't worth their while continuing on while the teams like Efapel and W52 go unchecked. LA Aluminios of course got their fingers burnt back in 2008 and stepped in to save Fercase (the Paredes team) back in 2009, which they have led as title sponsors since. Although obviously this is a relative measure, LA are one of the more reputable teams in Portugal, and since the end of the days they refer to (the 2008-9 latter heyday of Liberty Seguros) have been the one Portuguese team to have any success at the Volta ao Algarve (with Edgar Pinto and Amaro Antunes). That's not to say that they're a clean team per se, their historical roster includes the likes of Tino Zaballa, and there was that photo that surfaced of post-retirement Cândido wearing an LA-Antarte camisola amarela over his Salvatore Commesso gut.
If they don't think the Portuguese authorities are trying to curb doping, it's in their interest to cut their losses; if they feel (not unreasonably of course) that W52 et al are juicing up to the max and nothing will be done about it, their choices are to get out of it while they can, grin and bear it paycheck to paycheck, or go for the "if you can't beat 'em join 'em" mentality, which would be where your pre-emptive doping scandals might come in, but given that W52 and Tavira have got the football team sponsorships, they probably can't compete financially to do so, so they either continue on at the level they are now or just quit it. They've only got 9 riders on their books; if Antunes moves on, they've got very little left to offer; Hernâni Brôco is retiring and Alejandro Marque is 34 and hasn't looked like he gives a flying one after Movistar screwed him over to get their hands on Igor Antón. Those three guys account for pretty much all of their results, so with Brôco retiring and Marque's returns diminishing, they can offer less support to retain Antunes, and without any of them they may as well not be a pro team anyhow.