with a CPL(frozen ATPL) behind the trolley...
Did so as well for about half a year and had about 15 Collegues in the same situation... No problem, more likely welcome with most airlines I would say...
Did so with an airline with a red and white paintjob (a white cross at the fin...)
The time was great and learnt a lot about CRM and sure it will help me for the future, sitting in front and having an idea, what is going on behind...
Go for it, you won´t regret and as said already before, it is a great opportunity to make contacts!