Probably the most risky post I ever posted on AU, nevertheless need to get it of my chest...
Don't ask me how I got the impression, nor whom it involves, but there seems to be a tendency lately that people "exchange" favours.
No one on AU has any objection to an occasional sympathizing vote, nor with an upvote just because of the work that might have been involved in writing an answer.
I do object however strongly to a structural exchange of favours. Probably just inside the limits of what the system allows and detects. I don't like it, even resent it and I don't do it.
Please, please don't publicly upvote someone, often times on multiple posts at once, as an obvious "present", probably even without having read the answer(s). Just hoping someone will return the favour as a result. It is cheap, bad for the voting system and bad for the site.
If you vote, vote for the quality of an answer or question. Nothing more, nothing less.